Earth Fault Loop Impedance — help

Overview

The Earth Fault Loop Impedance calculator computes Zs, the total earth fault loop impedance of a circuit, and verifies that it is low enough for the protective device to disconnect the supply within the required time during an earth fault.

The calculator provides:

Zs calculation — total earth fault loop impedance using complex R+jX math
Transformer source impedance (optional) — from MVA rating and Z% with assumed X/R=10
Supplementary earthing (optional) — parallel combination of main and supplementary earth conductors
Zmax compliance check — Zs ≤ Uo / (In × trip multiplier)
Table 8.2 check — cable resistance limit by conductor size and CB rating
Table B1 check — cable length limit by conductor size and CB rating
Prospective fault current — If = Uo / Zs

Input Parameters

Parameter	Type	Default	Range	Description
`use_transformer`	Boolean	false	—	Include transformer source impedance in calculation
`transformer_mva`	Number	1.0	≥ 0.1	Transformer MVA rating (conditional on `use_transformer`)
`transformer_z_percent`	Number	6.0	1 – 15	Transformer impedance percentage (conditional on `use_transformer`)
`insulation_type`	Enum	pvc	pvc / xlpe	Cable insulation type: PVC (75°C) or XLPE (90°C)
`active_csa`	Enum	4	1 – 500 mm²	Active conductor cross-sectional area (19 standard sizes)
`earth_csa`	Enum	4	1 – 500 mm²	Main earth conductor cross-sectional area
`cable_length`	Number	50	0.1 – 10000 m	Cable route length in metres
`use_supplementary`	Boolean	false	—	Add supplementary earthing conductor in parallel
`supplementary_csa`	Enum	4	1 – 500 mm²	Supplementary conductor CSA (conditional on `use_supplementary`)
`nominal_voltage`	Number	230	1 – 1000 V	Nominal phase-to-neutral voltage (U_o)
`breaker_rating`	Number	20	0.5 – 600 A	Circuit breaker nominal current rating (I_n)
`trip_curve`	Enum	7.5 (C)	4 (B) / 7.5 (C) / 12.5 (D)	MCB trip curve multiplier

Output Results

Output	Symbol	Unit	Description
Loop Impedance	Z_s	Ω	Total earth fault loop impedance magnitude
Maximum Impedance	Z_max	Ω	Maximum allowed impedance = U_o / I_a
Fault Current	I_f	A	Prospective earth fault current = U_o / Z_s
Trip Current	I_a	A	I_n × trip curve multiplier
Component Impedances	Z_t, Z₁, Z₂, Z_e, Z_cable	Ω	All intermediate impedances as R + jX
Table 8.2 Check	—	PASS / FAIL / N/A	Cable resistance vs. maximum permitted resistance
Table B1 Check	—	PASS / FAIL / N/A	Cable length vs. maximum permitted length
Compliance Status	—	PASS / FAIL	All three checks must pass

Formulas

Transformer Source Impedance (optional)

\[ |Z_t| = \frac{Z\%}{100} \times \frac{V_{base}^2}{S_{base}} \]

where \(V_{base} = U_o \times \sqrt{3}\), \(S_{base} = \text{MVA} \times 10^6\). The impedance is resolved into R and X using an assumed X/R ratio of 10:

\[ R_t = \frac{|Z_t|}{\sqrt{1 + (X/R)^2}} \qquad X_t = R_t \times (X/R) \]

Conductor Impedance

\[ Z = R + jX = \left(r_{/km} \times \frac{L}{1000}\right) + j\left(x_{/km} \times \frac{L}{1000}\right) \]

where \(r_{/km}\) and \(x_{/km}\) are per-kilometre resistance and reactance from lookup tables (50 Hz), and \(L\) is the cable length in metres.

Parallel Earth Path (supplementary earthing)

\[ Z_e = \frac{Z_2 \times Z_3}{Z_2 + Z_3} \]

Complex parallel impedance of main earth (Z₂) and supplementary earth (Z₃).

Cable Loop Impedance

\[ Z_{cable} = Z_1 + Z_e \]

Sum of active conductor impedance and equivalent earth path impedance.

Total Earth Fault Loop Impedance

\[ Z_s = Z_t + Z_{cable} \]

If no transformer is selected, Z_t = 0.

Trip Current and Maximum Impedance

\[ I_a = I_n \times k_{trip} \qquad Z_{max} = \frac{U_o}{I_a} \]

The circuit is compliant when \(|Z_s| \leq Z_{max}\).

Prospective Fault Current

\[ I_f = \frac{U_o}{|Z_s|} \]

Data Tables

Resistance Data (Ω/km @ 50 Hz)

CSA (mm²)	1	1.5	2.5	4	6	10	16	25	35	50	70	95	120	150	185	240	300	400	500
PVC	25.8	16.5	9.01	5.61	3.75	2.23	1.4	0.884	0.638	0.471	0.327	0.236	0.188	0.153	0.123	0.0948	0.077	0.062	0.0506
XLPE	27	17.3	9.45	5.88	3.93	2.33	1.47	0.927	0.668	0.494	0.342	0.247	0.197	0.16	0.129	0.0991	0.0803	0.0646	0.0525

Reactance Data (Ω/km @ 50 Hz)

CSA (mm²)	1	1.5	2.5	4	6	10	16	25	35	50	70	95	120	150	185	240	300	400	500
PVC	0.119	0.111	0.102	0.102	0.0967	0.0906	0.0861	0.0853	0.0826	0.0797	0.077	0.0766	0.0743	0.0745	0.0744	0.0735	0.0732	0.0728	0.0723
XLPE	0.114	0.107	0.0988	0.093	0.0887	0.084	0.0805	0.0808	0.0786	0.0751	0.0741	0.0725	0.0713	0.0718	0.072	0.0709	0.0704	0.0702	0.0707

Table 8.2 — Maximum Cable Resistance (Ω)

Active CSA (mm²)	CB Rating (A)	Max R — B Curve	Max R — C Curve	Max R — D Curve
2.5	16	2.32	1.24	0.74
2.5	20	1.86	1.00	0.60
4	25	1.50	0.80	0.48
4	32	1.17	0.62	0.37
6	40	0.93	0.50	0.30
10	50	0.76	0.40	0.24
16	63	0.60	0.32	0.19

Table B1 — Maximum Cable Length (m)

Active CSA (mm²)	CB Rating (A)	Max L — B Curve	Max L — C Curve	Max L — D Curve
1	6	170	91	55
1	10	102	55	33
1.5	10	153	82	49
1.5	16	96	51	31
2.5	16	160	85	51
2.5	20	128	68	41
4	20	126	67	40
4	32	98	52	31
6	40	90	48	29
10	50	117	62	37
16	63	142	76	45
16	80	112	59	36
25	80	124	66	40
25	100	99	53	32
35	100	159	85	51
35	125	127	68	41
50	125	198	106	63
50	160	155	83	51
70	160	235	126	75
70	200	188	100	60

Worked Examples

The 10 examples below are the validation cases for this calculation. Each one was produced by the calculation engine from the inputs shown, every figure was checked against the independent reference quoted at the end of the example, and the same cases are run against every engine build (see validation scorecard, tool fe_calc_efli; worked examples for every calculation).

#	Case	Z_s (Ω)	Z_max (Ω)	I_f (A)	L_max (m)	Governing	Result
1	16 mm² with 6 mm² earth and 16 mm² supplementary earth, 63 A type C	0.1697	0.4868	1,355.7	76	table b1 route length	PASS
2	16 mm² PVC, 40 m, 80 A type D — exceeds Table B1	0.1122	0.2300	2,049.7	36	table b1 route length	FAIL
3	1 mm² PVC, 100 m, 6 A type B	5.1601	9.5833	44.6	170	table b1 route length	PASS
4	1.5 mm² XLPE, 100 m, 20 A type C — too long	3.4601	1.5333	66.5	44	earth fault loop impedance	FAIL
5	25 mm² XLPE sub-main at Uo = 400 V with a 2 MVA source	0.1114	0.5333	3,590.4	53	table b1 route length	PASS
6	2.5 mm² lighting circuit, 20 A type C	0.5406	1.5333	425.4	55	table 8 2 loop resistance	PASS
7	4 mm² with 2.5 mm² earth, 50 m, 32 A type C	0.7311	0.9583	314.6	42	table 8 2 loop resistance	FAIL
8	4 mm² PVC, 50 m, 20 A type C (help-page example 1)	0.5611	1.5333	409.9	67	table b1 route length	PASS
9	50 m circuit with a 1 MVA 6 % source transformer (help-page example 2)	0.5623	1.5333	409.0	67	table b1 route length	PASS
10	50 mm² PVC sub-main, 80 m, 100 A type C, 500 kVA 5 % source	0.1137	0.3067	2,022.2	221	earth fault loop impedance	PASS

Example 1 — 16 mm² with 6 mm² earth and 16 mm² supplementary earth, 63 A type C

A supplementary earth in parallel with the main earth lowers the earth-path impedance; all four checks pass.

Given: 16 mm² PVC active with 6 mm² earth plus a 16 mm² supplementary earth in parallel over the same route, route length 70 m, U_o = 230 V, 63 A type C MCB (trip multiple 7.5); no source impedance (circuit cable only). Engine c0034 (unrounded).

Source impedance	No source transformer given: Z_t = 0 — Z_s is the circuit cable's own contribution only
Active conductor	PVC 16 mm² table: 1.40 + j0.0861 Ω/km → Z₁ = (1.40 + j0.0861) × 70/1000 = 0.0980 + j0.0060 Ω
Earth conductor	PVC 6 mm² table: 3.75 + j0.0967 Ω/km → Z₂ = (3.75 + j0.0967) × 70/1000 = 0.2625 + j0.0068 Ω
Supplementary earth	PVC 16 mm² table: 1.40 + j0.0861 Ω/km → Z₃ = 0.0980 + j0.0060 Ω; in parallel: Z_e = Z₂·Z₃ / (Z₂ + Z₃) = (0.2625 + j0.0068)(0.0980 + j0.0060) / (0.3605 + j0.0128) = 0.0714 + j0.0037 Ω
Cable loop	Z_cable = Z₁ + Z_e = (0.0980 + j0.0060) + (0.0714 + j0.0037) = 0.1694 + j0.0097 Ω; loop resistance R = 0.1694 Ω
Loop impedance	Z_s = \|Z_t + Z_cable\| = \|0.1694 + j0.0097\| = √(0.1694² + 0.0097²) = 0.1697 Ω
Trip current	I_a = I_n × k = 63 × 7.5 = 472.5 A; Z_max = U_o / I_a = 230 / 472.5 = 0.4868 Ω
Zs ≤ Zmax	AS/NZS 3000 Clause 8.3.9 basis, Z_s at 34.9 % of Z_max → 0.1697 vs limit 0.4868 Ω PASS
Fault current	I_f = U_o / Z_s = 230 / 0.1697 = 1,355.7 A ≥ I_a → 1,355.7 vs limit 472.5 A PASS
Table 8.2	AS/NZS 3000 Table 8.2 row (16 mm², 63 A, type C) maximum loop resistance 0.32 Ω vs R = 0.1694 Ω → 0.1694 vs limit 0.3200 Ω PASS
Table B1	AS/NZS 3000 Table B1 row (16 mm², 63 A, type C) maximum length 76 m vs route 70 m → 70 vs limit 76 m PASS
Max route length	Z_s = Z_max when \|Z_t + L × (0.00242 + j0.00014)\| = 0.4868 Ω → L = 200 m (≈ 0.4868 / 0.00242 Ω/m); Table 8.2: 0.32 / 0.00242 Ω/m = 132.2 → 132 m; Table B1: 76 m. Governing: 76 m (AS/NZS 3000 Table B1 length)
Result	4/4 checks pass → PASS; Z_s 0.1697 Ω vs Z_max 0.4868 Ω; max route 76 m (AS/NZS 3000 Table B1 length); governing: table b1 route length
Reference	Hand calculation (help-page formulas and tables): no source impedance (Zt = 0); PVC 16 mm² 1.4 + j0.0861 Ω/km → Z1 = 0.09800 + j0.00603 Ω; earth 6 mm² 3.75 + j0.0967 Ω/km → Z2 = 0.26250 + j0.00677 Ω; supplementary 16 mm² Z3 = 0.09800 + j0.00603 Ω; Ze = Z2·Z3/(Z2+Z3) = 0.07138 + j0.00370 Ω; Zloop = 0.16938 + j0.00972 Ω; Zs = \|0.16938 + j0.00972\| = 0.16966 Ω; Ia = 63 × 7.5 = 472.5 A, Zmax = 230/472.5 = 0.48677 Ω; If = 230/0.1697 = 1355.7 A; Zs = Zmax at 200.8 m → 200 m; Table 8.2 (16 mm², 63 A, C) 0.32 Ω: Rloop 0.1694 Ω ≤ limit; 0.32/0.00242 = 132.2 → 132 m; Table B1 (16 mm², 63 A, C) 76 m: L 70 m ≤ limit (validation case `c0034-16-6mm2-pvc-70m-63a-c-supp-16`)

Example 2 — 16 mm² PVC, 40 m, 80 A type D — exceeds Table B1

Type D (12.5 × In) on a 16 mm² circuit: Zs is half of Zmax, Table 8.2 has no 80 A row, but the 40 m run exceeds the Table B1 length so the circuit fails on the length table.

Given: 16 mm² PVC active with 16 mm² earth, route length 40 m, U_o = 230 V, 80 A type D MCB (trip multiple 12.5); no source impedance (circuit cable only). Engine c0034 (unrounded).

Source impedance	No source transformer given: Z_t = 0 — Z_s is the circuit cable's own contribution only
Active conductor	PVC 16 mm² table: 1.40 + j0.0861 Ω/km → Z₁ = (1.40 + j0.0861) × 40/1000 = 0.0560 + j0.0034 Ω
Earth conductor	Same size as the active: Z₂ = Z₁ = 0.0560 + j0.0034 Ω
Cable loop	Z_cable = Z₁ + Z_e = (0.0560 + j0.0034) + (0.0560 + j0.0034) = 0.1120 + j0.0069 Ω; loop resistance R = 0.1120 Ω
Loop impedance	Z_s = \|Z_t + Z_cable\| = \|0.1120 + j0.0069\| = √(0.1120² + 0.0069²) = 0.1122 Ω
Trip current	I_a = I_n × k = 80 × 12.5 = 1,000 A; Z_max = U_o / I_a = 230 / 1,000 = 0.2300 Ω
Zs ≤ Zmax	AS/NZS 3000 Clause 8.3.9 basis, Z_s at 48.8 % of Z_max → 0.1122 vs limit 0.2300 Ω PASS
Fault current	I_f = U_o / Z_s = 230 / 0.1122 = 2,049.7 A ≥ I_a → 2,049.7 vs limit 1,000.0 A PASS
Table 8.2	No AS/NZS 3000 Table 8.2 row for 16 mm², 80 A, type D — resistance table not checked
Table B1	AS/NZS 3000 Table B1 row (16 mm², 80 A, type D) maximum length 36 m vs route 40 m → 40 vs limit 36 m FAIL
Max route length	Z_s = Z_max when \|Z_t + L × (0.00280 + j0.00017)\| = 0.2300 Ω → L = 81 m (≈ 0.2300 / 0.00281 Ω/m); Table B1: 36 m. Governing: 36 m (AS/NZS 3000 Table B1 length)
Result	2/3 checks pass → FAIL; Z_s 0.1122 Ω vs Z_max 0.2300 Ω; max route 36 m (AS/NZS 3000 Table B1 length); governing: table b1 route length. Fails: table_b1_route_length. Options: shorten the route below 36 m, increase the active/earth size, use a lower-multiple curve, or provide additional protection such as an RCD (not assessed by this engine).
Reference	Hand calculation (help-page formulas and tables): no source impedance (Zt = 0); PVC 16 mm² 1.4 + j0.0861 Ω/km → Z1 = 0.05600 + j0.00344 Ω; earth 16 mm² same → Z2 = Z1; Zloop = 0.11200 + j0.00689 Ω; Zs = \|0.11200 + j0.00689\| = 0.11221 Ω; Ia = 80 × 12.5 = 1000 A, Zmax = 230/1000 = 0.23000 Ω; If = 230/0.1122 = 2049.7 A; Zs = Zmax at 82.0 m → 81 m; Table 8.2 has no row for 16 mm² / 80 A; Table B1 (16 mm², 80 A, D) 36 m: L 40 m > limit (validation case `c0034-16mm2-pvc-40m-80a-d-fail`)

Example 3 — 1 mm² PVC, 100 m, 6 A type B

Smallest conductor on a type B breaker: Zs is well under Zmax and the Table B1 length (not Zs) sets the maximum route.

Given: 1 mm² PVC active with 1 mm² earth, route length 100 m, U_o = 230 V, 6 A type B MCB (trip multiple 4); no source impedance (circuit cable only). Engine c0034 (unrounded).

Source impedance	No source transformer given: Z_t = 0 — Z_s is the circuit cable's own contribution only
Active conductor	PVC 1 mm² table: 25.8 + j0.119 Ω/km → Z₁ = (25.8 + j0.119) × 100/1000 = 2.5800 + j0.0119 Ω
Earth conductor	Same size as the active: Z₂ = Z₁ = 2.5800 + j0.0119 Ω
Cable loop	Z_cable = Z₁ + Z_e = (2.5800 + j0.0119) + (2.5800 + j0.0119) = 5.1600 + j0.0238 Ω; loop resistance R = 5.1600 Ω
Loop impedance	Z_s = \|Z_t + Z_cable\| = \|5.1600 + j0.0238\| = √(5.1600² + 0.0238²) = 5.1601 Ω
Trip current	I_a = I_n × k = 6 × 4 = 24 A; Z_max = U_o / I_a = 230 / 24 = 9.5833 Ω
Zs ≤ Zmax	AS/NZS 3000 Clause 8.3.9 basis, Z_s at 53.8 % of Z_max → 5.1601 vs limit 9.5833 Ω PASS
Fault current	I_f = U_o / Z_s = 230 / 5.1601 = 44.6 A ≥ I_a → 44.6 vs limit 24.0 A PASS
Table 8.2	No AS/NZS 3000 Table 8.2 row for 1 mm², 6 A, type B — resistance table not checked
Table B1	AS/NZS 3000 Table B1 row (1 mm², 6 A, type B) maximum length 170 m vs route 100 m → 100 vs limit 170 m PASS
Max route length	Z_s = Z_max when \|Z_t + L × (0.05160 + j0.00024)\| = 9.5833 Ω → L = 185 m (≈ 9.5833 / 0.05160 Ω/m); Table B1: 170 m. Governing: 170 m (AS/NZS 3000 Table B1 length)
Result	3/3 checks pass → PASS; Z_s 5.1601 Ω vs Z_max 9.5833 Ω; max route 170 m (AS/NZS 3000 Table B1 length); governing: table b1 route length
Reference	Hand calculation (help-page formulas and tables): no source impedance (Zt = 0); PVC 1 mm² 25.8 + j0.119 Ω/km → Z1 = 2.58000 + j0.01190 Ω; earth 1 mm² same → Z2 = Z1; Zloop = 5.16000 + j0.02380 Ω; Zs = \|5.16000 + j0.02380\| = 5.16005 Ω; Ia = 6 × 4 = 24 A, Zmax = 230/24 = 9.58333 Ω; If = 230/5.1601 = 44.6 A; Zs = Zmax at 185.7 m → 185 m; Table 8.2 has no row for 1 mm² / 6 A; Table B1 (1 mm², 6 A, B) 170 m: L 100 m ≤ limit (validation case `c0034-1mm2-pvc-100m-6a-b`)

Example 4 — 1.5 mm² XLPE, 100 m, 20 A type C — too long

A long run on an undersized conductor fails Zs ≤ Zmax outright; no table row exists for 1.5 mm² at 20 A so only the two impedance checks run.

Given: 1.5 mm² XLPE active with 1.5 mm² earth, route length 100 m, U_o = 230 V, 20 A type C MCB (trip multiple 7.5); no source impedance (circuit cable only). Engine c0034 (unrounded).

Source impedance	No source transformer given: Z_t = 0 — Z_s is the circuit cable's own contribution only
Active conductor	XLPE 1.5 mm² table: 17.3 + j0.107 Ω/km → Z₁ = (17.3 + j0.107) × 100/1000 = 1.7300 + j0.0107 Ω
Earth conductor	Same size as the active: Z₂ = Z₁ = 1.7300 + j0.0107 Ω
Cable loop	Z_cable = Z₁ + Z_e = (1.7300 + j0.0107) + (1.7300 + j0.0107) = 3.4600 + j0.0214 Ω; loop resistance R = 3.4600 Ω
Loop impedance	Z_s = \|Z_t + Z_cable\| = \|3.4600 + j0.0214\| = √(3.4600² + 0.0214²) = 3.4601 Ω
Trip current	I_a = I_n × k = 20 × 7.5 = 150 A; Z_max = U_o / I_a = 230 / 150 = 1.5333 Ω
Zs ≤ Zmax	AS/NZS 3000 Clause 8.3.9 basis, Z_s at 225.7 % of Z_max → 3.4601 vs limit 1.5333 Ω FAIL
Fault current	I_f = U_o / Z_s = 230 / 3.4601 = 66.5 A ≥ I_a → 66.5 vs limit 150.0 A FAIL
Table 8.2	No AS/NZS 3000 Table 8.2 row for 1.5 mm², 20 A, type C — resistance table not checked
Table B1	No AS/NZS 3000 Table B1 row for 1.5 mm², 20 A, type C — length table not checked
Max route length	Z_s = Z_max when \|Z_t + L × (0.03460 + j0.00021)\| = 1.5333 Ω → L = 44 m (≈ 1.5333 / 0.03460 Ω/m). Governing: 44 m (Zs = Zmax)
Result	0/2 checks pass → FAIL; Z_s 3.4601 Ω vs Z_max 1.5333 Ω; max route 44 m (Zs = Zmax); governing: earth fault loop impedance. Fails: earth_fault_loop_impedance, disconnection_instantaneous_trip. Options: shorten the route below 44 m, increase the active/earth size, use a lower-multiple curve, or provide additional protection such as an RCD (not assessed by this engine).
Reference	Hand calculation (help-page formulas and tables): no source impedance (Zt = 0); XLPE 1.5 mm² 17.3 + j0.107 Ω/km → Z1 = 1.73000 + j0.01070 Ω; earth 1.5 mm² same → Z2 = Z1; Zloop = 3.46000 + j0.02140 Ω; Zs = \|3.46000 + j0.02140\| = 3.46007 Ω; Ia = 20 × 7.5 = 150 A, Zmax = 230/150 = 1.53333 Ω; If = 230/3.4601 = 66.5 A; Zs = Zmax at 44.3 m → 44 m; Table 8.2 has no row for 1.5 mm² / 20 A; Table B1 has no row for 1.5 mm² / 20 A (validation case `c0034-1mm5-xlpe-100m-20a-c-fail`)

Example 5 — 25 mm² XLPE sub-main at Uo = 400 V with a 2 MVA source

A 400 V phase-to-earth system: Zmax scales with Uo, the transformer impedance is computed at 400 V and Table B1 (25 mm², 100 A) applies.

Given: 25 mm² XLPE active with 16 mm² earth, route length 45 m, U_o = 400 V, 100 A type C MCB (trip multiple 7.5); 2 MVA, 6 % source transformer (X/R 10). Engine c0034 (unrounded).

Source impedance	V_base = 400 × √3 = 692.8 V; \|Z_t\| = 6/100 × 692.8² / (2 × 10⁶) = 0.01440 Ω; with X/R = 10: R_t = 0.01440 / √(1 + 10²) = 0.00143 Ω, X_t = 10 × R_t = 0.01433 Ω
Active conductor	XLPE 25 mm² table: 0.927 + j0.0808 Ω/km → Z₁ = (0.927 + j0.0808) × 45/1000 = 0.0417 + j0.0036 Ω
Earth conductor	XLPE 16 mm² table: 1.47 + j0.0805 Ω/km → Z₂ = (1.47 + j0.0805) × 45/1000 = 0.0662 + j0.0036 Ω
Cable loop	Z_cable = Z₁ + Z_e = (0.0417 + j0.0036) + (0.0662 + j0.0036) = 0.1079 + j0.0073 Ω; loop resistance R = 0.1079 Ω
Loop impedance	Z_s = \|Z_t + Z_cable\| = \|0.1093 + j0.0216\| = √(0.1093² + 0.0216²) = 0.1114 Ω
Trip current	I_a = I_n × k = 100 × 7.5 = 750 A; Z_max = U_o / I_a = 400 / 750 = 0.5333 Ω
Zs ≤ Zmax	AS/NZS 3000 Clause 8.3.9 basis, Z_s at 20.9 % of Z_max → 0.1114 vs limit 0.5333 Ω PASS
Fault current	I_f = U_o / Z_s = 400 / 0.1114 = 3,590.4 A ≥ I_a → 3,590.4 vs limit 750.0 A PASS
Table 8.2	No AS/NZS 3000 Table 8.2 row for 25 mm², 100 A, type C — resistance table not checked
Table B1	AS/NZS 3000 Table B1 row (25 mm², 100 A, type C) maximum length 53 m vs route 45 m → 45 vs limit 53 m PASS
Max route length	Z_s = Z_max when \|Z_t + L × (0.00240 + j0.00016)\| = 0.5333 Ω → L = 220 m; Table B1: 53 m. Governing: 53 m (AS/NZS 3000 Table B1 length)
Result	3/3 checks pass → PASS; Z_s 0.1114 Ω vs Z_max 0.5333 Ω; max route 53 m (AS/NZS 3000 Table B1 length); governing: table b1 route length
Reference	Hand calculation (help-page formulas and tables): Vbase = 400 × √3 = 692.8 V, \|Zt\| = 6/100 × 692.8² / 2,000,000 = 0.01440 Ω, Rt = 0.01440/√101 = 0.00143 Ω, Xt = 0.01433 Ω; XLPE 25 mm² 0.927 + j0.0808 Ω/km → Z1 = 0.04172 + j0.00364 Ω; earth 16 mm² 1.47 + j0.0805 Ω/km → Z2 = 0.06615 + j0.00362 Ω; Zloop = 0.10787 + j0.00726 Ω; Zs = \|0.10930 + j0.02159\| = 0.11141 Ω; Ia = 100 × 7.5 = 750 A, Zmax = 400/750 = 0.53333 Ω; If = 400/0.1114 = 3590.4 A; Zs = Zmax at 220.9 m → 220 m; Table 8.2 has no row for 25 mm² / 100 A; Table B1 (25 mm², 100 A, C) 53 m: L 45 m ≤ limit (validation case `c0034-25-16mm2-xlpe-45m-100a-c-400v-2mva`)

Example 6 — 2.5 mm² lighting circuit, 20 A type C

A short PVC final sub-circuit with equal active and earth; both AS/NZS 3000 tables apply and Table 8.2 sets the maximum route length.

Given: 2.5 mm² PVC active with 2.5 mm² earth, route length 30 m, U_o = 230 V, 20 A type C MCB (trip multiple 7.5); no source impedance (circuit cable only). Engine c0034 (unrounded).

Source impedance	No source transformer given: Z_t = 0 — Z_s is the circuit cable's own contribution only
Active conductor	PVC 2.5 mm² table: 9.01 + j0.102 Ω/km → Z₁ = (9.01 + j0.102) × 30/1000 = 0.2703 + j0.0031 Ω
Earth conductor	Same size as the active: Z₂ = Z₁ = 0.2703 + j0.0031 Ω
Cable loop	Z_cable = Z₁ + Z_e = (0.2703 + j0.0031) + (0.2703 + j0.0031) = 0.5406 + j0.0061 Ω; loop resistance R = 0.5406 Ω
Loop impedance	Z_s = \|Z_t + Z_cable\| = \|0.5406 + j0.0061\| = √(0.5406² + 0.0061²) = 0.5406 Ω
Trip current	I_a = I_n × k = 20 × 7.5 = 150 A; Z_max = U_o / I_a = 230 / 150 = 1.5333 Ω
Zs ≤ Zmax	AS/NZS 3000 Clause 8.3.9 basis, Z_s at 35.3 % of Z_max → 0.5406 vs limit 1.5333 Ω PASS
Fault current	I_f = U_o / Z_s = 230 / 0.5406 = 425.4 A ≥ I_a → 425.4 vs limit 150.0 A PASS
Table 8.2	AS/NZS 3000 Table 8.2 row (2.5 mm², 20 A, type C) maximum loop resistance 1.00 Ω vs R = 0.5406 Ω → 0.5406 vs limit 1.0000 Ω PASS
Table B1	AS/NZS 3000 Table B1 row (2.5 mm², 20 A, type C) maximum length 68 m vs route 30 m → 30 vs limit 68 m PASS
Max route length	Z_s = Z_max when \|Z_t + L × (0.01802 + j0.00020)\| = 1.5333 Ω → L = 85 m (≈ 1.5333 / 0.01802 Ω/m); Table 8.2: 1.00 / 0.01802 Ω/m = 55.5 → 55 m; Table B1: 68 m. Governing: 55 m (AS/NZS 3000 Table 8.2 resistance)
Result	4/4 checks pass → PASS; Z_s 0.5406 Ω vs Z_max 1.5333 Ω; max route 55 m (AS/NZS 3000 Table 8.2 resistance); governing: table 8 2 loop resistance
Reference	Hand calculation (help-page formulas and tables): no source impedance (Zt = 0); PVC 2.5 mm² 9.01 + j0.102 Ω/km → Z1 = 0.27030 + j0.00306 Ω; earth 2.5 mm² same → Z2 = Z1; Zloop = 0.54060 + j0.00612 Ω; Zs = \|0.54060 + j0.00612\| = 0.54063 Ω; Ia = 20 × 7.5 = 150 A, Zmax = 230/150 = 1.53333 Ω; If = 230/0.5406 = 425.4 A; Zs = Zmax at 85.1 m → 85 m; Table 8.2 (2.5 mm², 20 A, C) 1.00 Ω: Rloop 0.5406 Ω ≤ limit; 1.00/0.01802 = 55.5 → 55 m; Table B1 (2.5 mm², 20 A, C) 68 m: L 30 m ≤ limit (validation case `c0034-2mm5-pvc-30m-20a-c`)

Example 7 — 4 mm² with 2.5 mm² earth, 50 m, 32 A type C

Reduced earth conductor: Zs clears Zmax but the loop resistance exceeds the Table 8.2 row, so the circuit fails on the table check.

Given: 4 mm² PVC active with 2.5 mm² earth, route length 50 m, U_o = 230 V, 32 A type C MCB (trip multiple 7.5); no source impedance (circuit cable only). Engine c0034 (unrounded).

Source impedance	No source transformer given: Z_t = 0 — Z_s is the circuit cable's own contribution only
Active conductor	PVC 4 mm² table: 5.61 + j0.102 Ω/km → Z₁ = (5.61 + j0.102) × 50/1000 = 0.2805 + j0.0051 Ω
Earth conductor	PVC 2.5 mm² table: 9.01 + j0.102 Ω/km → Z₂ = (9.01 + j0.102) × 50/1000 = 0.4505 + j0.0051 Ω
Cable loop	Z_cable = Z₁ + Z_e = (0.2805 + j0.0051) + (0.4505 + j0.0051) = 0.7310 + j0.0102 Ω; loop resistance R = 0.7310 Ω
Loop impedance	Z_s = \|Z_t + Z_cable\| = \|0.7310 + j0.0102\| = √(0.7310² + 0.0102²) = 0.7311 Ω
Trip current	I_a = I_n × k = 32 × 7.5 = 240 A; Z_max = U_o / I_a = 230 / 240 = 0.9583 Ω
Zs ≤ Zmax	AS/NZS 3000 Clause 8.3.9 basis, Z_s at 76.3 % of Z_max → 0.7311 vs limit 0.9583 Ω PASS
Fault current	I_f = U_o / Z_s = 230 / 0.7311 = 314.6 A ≥ I_a → 314.6 vs limit 240.0 A PASS
Table 8.2	AS/NZS 3000 Table 8.2 row (4 mm², 32 A, type C) maximum loop resistance 0.62 Ω vs R = 0.7310 Ω → 0.7310 vs limit 0.6200 Ω FAIL
Table B1	AS/NZS 3000 Table B1 row (4 mm², 32 A, type C) maximum length 52 m vs route 50 m → 50 vs limit 52 m PASS
Max route length	Z_s = Z_max when \|Z_t + L × (0.01462 + j0.00020)\| = 0.9583 Ω → L = 65 m (≈ 0.9583 / 0.01462 Ω/m); Table 8.2: 0.62 / 0.01462 Ω/m = 42.4 → 42 m; Table B1: 52 m. Governing: 42 m (AS/NZS 3000 Table 8.2 resistance)
Result	3/4 checks pass → FAIL; Z_s 0.7311 Ω vs Z_max 0.9583 Ω; max route 42 m (AS/NZS 3000 Table 8.2 resistance); governing: table 8 2 loop resistance. Fails: table_8_2_loop_resistance. Options: shorten the route below 42 m, increase the active/earth size, use a lower-multiple curve, or provide additional protection such as an RCD (not assessed by this engine).
Reference	Hand calculation (help-page formulas and tables): no source impedance (Zt = 0); PVC 4 mm² 5.61 + j0.102 Ω/km → Z1 = 0.28050 + j0.00510 Ω; earth 2.5 mm² 9.01 + j0.102 Ω/km → Z2 = 0.45050 + j0.00510 Ω; Zloop = 0.73100 + j0.01020 Ω; Zs = \|0.73100 + j0.01020\| = 0.73107 Ω; Ia = 32 × 7.5 = 240 A, Zmax = 230/240 = 0.95833 Ω; If = 230/0.7311 = 314.6 A; Zs = Zmax at 65.5 m → 65 m; Table 8.2 (4 mm², 32 A, C) 0.62 Ω: Rloop 0.7310 Ω > limit; 0.62/0.01462 = 42.4 → 42 m; Table B1 (4 mm², 32 A, C) 52 m: L 50 m ≤ limit (validation case `c0034-4-2mm5-pvc-50m-32a-c`)

Example 8 — 4 mm² PVC, 50 m, 20 A type C (help-page example 1)

4 mm² on a 20 A breaker has a Table B1 row but no Table 8.2 row, so only the length table is appended to the Zs check.

Given: 4 mm² PVC active with 4 mm² earth, route length 50 m, U_o = 230 V, 20 A type C MCB (trip multiple 7.5); no source impedance (circuit cable only). Engine c0034 (unrounded).

Source impedance	No source transformer given: Z_t = 0 — Z_s is the circuit cable's own contribution only
Active conductor	PVC 4 mm² table: 5.61 + j0.102 Ω/km → Z₁ = (5.61 + j0.102) × 50/1000 = 0.2805 + j0.0051 Ω
Earth conductor	Same size as the active: Z₂ = Z₁ = 0.2805 + j0.0051 Ω
Cable loop	Z_cable = Z₁ + Z_e = (0.2805 + j0.0051) + (0.2805 + j0.0051) = 0.5610 + j0.0102 Ω; loop resistance R = 0.5610 Ω
Loop impedance	Z_s = \|Z_t + Z_cable\| = \|0.5610 + j0.0102\| = √(0.5610² + 0.0102²) = 0.5611 Ω
Trip current	I_a = I_n × k = 20 × 7.5 = 150 A; Z_max = U_o / I_a = 230 / 150 = 1.5333 Ω
Zs ≤ Zmax	AS/NZS 3000 Clause 8.3.9 basis, Z_s at 36.6 % of Z_max → 0.5611 vs limit 1.5333 Ω PASS
Fault current	I_f = U_o / Z_s = 230 / 0.5611 = 409.9 A ≥ I_a → 409.9 vs limit 150.0 A PASS
Table 8.2	No AS/NZS 3000 Table 8.2 row for 4 mm², 20 A, type C — resistance table not checked
Table B1	AS/NZS 3000 Table B1 row (4 mm², 20 A, type C) maximum length 67 m vs route 50 m → 50 vs limit 67 m PASS
Max route length	Z_s = Z_max when \|Z_t + L × (0.01122 + j0.00020)\| = 1.5333 Ω → L = 136 m (≈ 1.5333 / 0.01122 Ω/m); Table B1: 67 m. Governing: 67 m (AS/NZS 3000 Table B1 length)
Result	3/3 checks pass → PASS; Z_s 0.5611 Ω vs Z_max 1.5333 Ω; max route 67 m (AS/NZS 3000 Table B1 length); governing: table b1 route length
Reference	Hand calculation (help-page formulas and tables): no source impedance (Zt = 0); PVC 4 mm² 5.61 + j0.102 Ω/km → Z1 = 0.28050 + j0.00510 Ω; earth 4 mm² same → Z2 = Z1; Zloop = 0.56100 + j0.01020 Ω; Zs = \|0.56100 + j0.01020\| = 0.56109 Ω; Ia = 20 × 7.5 = 150 A, Zmax = 230/150 = 1.53333 Ω; If = 230/0.5611 = 409.9 A; Zs = Zmax at 136.6 m → 136 m; Table 8.2 has no row for 4 mm² / 20 A; Table B1 (4 mm², 20 A, C) 67 m: L 50 m ≤ limit (validation case `c0034-4mm2-pvc-50m-20a-c`)

Example 9 — 50 m circuit with a 1 MVA 6 % source transformer (help-page example 2)

Adds the supply transformer impedance (X/R 10) to the loop; the extra 0.0095 Ω barely moves Zs.

Given: 4 mm² PVC active with 4 mm² earth, route length 50 m, U_o = 230 V, 20 A type C MCB (trip multiple 7.5); 1 MVA, 6 % source transformer (X/R 10). Engine c0034 (unrounded).

Source impedance	V_base = 230 × √3 = 398.4 V; \|Z_t\| = 6/100 × 398.4² / (1 × 10⁶) = 0.00952 Ω; with X/R = 10: R_t = 0.00952 / √(1 + 10²) = 0.00095 Ω, X_t = 10 × R_t = 0.00947 Ω
Active conductor	PVC 4 mm² table: 5.61 + j0.102 Ω/km → Z₁ = (5.61 + j0.102) × 50/1000 = 0.2805 + j0.0051 Ω
Earth conductor	Same size as the active: Z₂ = Z₁ = 0.2805 + j0.0051 Ω
Cable loop	Z_cable = Z₁ + Z_e = (0.2805 + j0.0051) + (0.2805 + j0.0051) = 0.5610 + j0.0102 Ω; loop resistance R = 0.5610 Ω
Loop impedance	Z_s = \|Z_t + Z_cable\| = \|0.5619 + j0.0197\| = √(0.5619² + 0.0197²) = 0.5623 Ω
Trip current	I_a = I_n × k = 20 × 7.5 = 150 A; Z_max = U_o / I_a = 230 / 150 = 1.5333 Ω
Zs ≤ Zmax	AS/NZS 3000 Clause 8.3.9 basis, Z_s at 36.7 % of Z_max → 0.5623 vs limit 1.5333 Ω PASS
Fault current	I_f = U_o / Z_s = 230 / 0.5623 = 409.0 A ≥ I_a → 409.0 vs limit 150.0 A PASS
Table 8.2	No AS/NZS 3000 Table 8.2 row for 4 mm², 20 A, type C — resistance table not checked
Table B1	AS/NZS 3000 Table B1 row (4 mm², 20 A, type C) maximum length 67 m vs route 50 m → 50 vs limit 67 m PASS
Max route length	Z_s = Z_max when \|Z_t + L × (0.01122 + j0.00020)\| = 1.5333 Ω → L = 136 m; Table B1: 67 m. Governing: 67 m (AS/NZS 3000 Table B1 length)
Result	3/3 checks pass → PASS; Z_s 0.5623 Ω vs Z_max 1.5333 Ω; max route 67 m (AS/NZS 3000 Table B1 length); governing: table b1 route length
Reference	Hand calculation (help-page formulas and tables): Vbase = 230 × √3 = 398.4 V, \|Zt\| = 6/100 × 398.4² / 1,000,000 = 0.00952 Ω, Rt = 0.00952/√101 = 0.00095 Ω, Xt = 0.00947 Ω; PVC 4 mm² 5.61 + j0.102 Ω/km → Z1 = 0.28050 + j0.00510 Ω; earth 4 mm² same → Z2 = Z1; Zloop = 0.56100 + j0.01020 Ω; Zs = \|0.56195 + j0.01967\| = 0.56229 Ω; Ia = 20 × 7.5 = 150 A, Zmax = 230/150 = 1.53333 Ω; If = 230/0.5623 = 409.0 A; Zs = Zmax at 136.5 m → 136 m; Table 8.2 has no row for 4 mm² / 20 A; Table B1 (4 mm², 20 A, C) 67 m: L 50 m ≤ limit (validation case `c0034-4mm2-pvc-50m-20a-c-1mva`)

Example 10 — 50 mm² PVC sub-main, 80 m, 100 A type C, 500 kVA 5 % source

No table row for 50 mm² at 100 A: the maximum route length comes only from solving Zs = Zmax with the transformer impedance included.

Given: 50 mm² PVC active with 25 mm² earth, route length 80 m, U_o = 230 V, 100 A type C MCB (trip multiple 7.5); 0.5 MVA, 5 % source transformer (X/R 10). Engine c0034 (unrounded).

Source impedance	V_base = 230 × √3 = 398.4 V; \|Z_t\| = 5/100 × 398.4² / (0.5 × 10⁶) = 0.01587 Ω; with X/R = 10: R_t = 0.01587 / √(1 + 10²) = 0.00158 Ω, X_t = 10 × R_t = 0.01579 Ω
Active conductor	PVC 50 mm² table: 0.471 + j0.0797 Ω/km → Z₁ = (0.471 + j0.0797) × 80/1000 = 0.0377 + j0.0064 Ω
Earth conductor	PVC 25 mm² table: 0.884 + j0.0853 Ω/km → Z₂ = (0.884 + j0.0853) × 80/1000 = 0.0707 + j0.0068 Ω
Cable loop	Z_cable = Z₁ + Z_e = (0.0377 + j0.0064) + (0.0707 + j0.0068) = 0.1084 + j0.0132 Ω; loop resistance R = 0.1084 Ω
Loop impedance	Z_s = \|Z_t + Z_cable\| = \|0.1100 + j0.0290\| = √(0.1100² + 0.0290²) = 0.1137 Ω
Trip current	I_a = I_n × k = 100 × 7.5 = 750 A; Z_max = U_o / I_a = 230 / 750 = 0.3067 Ω
Zs ≤ Zmax	AS/NZS 3000 Clause 8.3.9 basis, Z_s at 37.1 % of Z_max → 0.1137 vs limit 0.3067 Ω PASS
Fault current	I_f = U_o / Z_s = 230 / 0.1137 = 2,022.2 A ≥ I_a → 2,022.2 vs limit 750.0 A PASS
Table 8.2	No AS/NZS 3000 Table 8.2 row for 50 mm², 100 A, type C — resistance table not checked
Table B1	No AS/NZS 3000 Table B1 row for 50 mm², 100 A, type C — length table not checked
Max route length	Z_s = Z_max when \|Z_t + L × (0.00135 + j0.00016)\| = 0.3067 Ω → L = 221 m. Governing: 221 m (Zs = Zmax)
Result	2/2 checks pass → PASS; Z_s 0.1137 Ω vs Z_max 0.3067 Ω; max route 221 m (Zs = Zmax); governing: earth fault loop impedance
Reference	Hand calculation (help-page formulas and tables): Vbase = 230 × √3 = 398.4 V, \|Zt\| = 5/100 × 398.4² / 500,000 = 0.01587 Ω, Rt = 0.01587/√101 = 0.00158 Ω, Xt = 0.01579 Ω; PVC 50 mm² 0.471 + j0.0797 Ω/km → Z1 = 0.03768 + j0.00638 Ω; earth 25 mm² 0.884 + j0.0853 Ω/km → Z2 = 0.07072 + j0.00682 Ω; Zloop = 0.10840 + j0.01320 Ω; Zs = \|0.10998 + j0.02899\| = 0.11374 Ω; Ia = 100 × 7.5 = 750 A, Zmax = 230/750 = 0.30667 Ω; If = 230/0.1137 = 2022.2 A; Zs = Zmax at 221.8 m → 221 m; Table 8.2 has no row for 50 mm² / 100 A; Table B1 has no row for 50 mm² / 100 A (validation case `c0034-50-25mm2-pvc-80m-100a-c-0mva5`)

Standards & References

IEC 60364-4-41 — Protection against electric shock. Defines earth fault loop impedance requirements for automatic disconnection.
BS 7671 (IET Wiring Regulations) — Requirements for electrical installations. Tables 41.2–41.4 provide maximum Zs values.
AS/NZS 3000:2018 — Electrical installations (Wiring Rules). Section 5.8 covers earth fault loop impedance requirements.
AS/NZS 3008.1:2017 — Selection of cables. Provides conductor impedance data and Table 8.2 / Table B1 compliance checks.

Tips & Limitations

Frequency: All impedance values assume 50 Hz supply. For 60 Hz systems, reactance values will differ slightly.

X/R ratio: Transformer impedance uses an assumed X/R ratio of 10, which is typical for distribution transformers. For large power transformers, the actual X/R ratio from the test certificate should be used.

Table checks: Tables 8.2 and B1 only cover common CSA/CB rating combinations. If the check shows “N/A”, the combination is not listed in the table — the Zmax impedance check still applies.

Temperature effects: Conductor resistance increases with temperature. The resistance values used are for maximum operating temperature (75°C for PVC, 90°C for XLPE). Actual resistance at 20°C will be lower.

Single-phase circuits only: This calculator assumes a single-phase earth fault loop (phase-earth). For three-phase circuits, the earth fault loop impedance is calculated identically for each phase conductor.

Developer Guide — Architecture

File Layout

components/c0034_earth_fault_loop_impedance/
├─ __init__.py              # Docstring
├─ apps.py                  # Django AppConfig
├─ calculations.py          # Pure Python — all math, no Django
├─ component.py             # Schema, Calculator class, builders, registration
├─ equations.py             # LaTeX equation templates
└─ templates/.../sidebar_form.html  # Vue 3 sidebar form

Data flow: Sidebar form → EarthFaultLoopImpedanceCalculator.calculate() → calculate_earth_fault_loop_impedance() (pure Python) → results dict → equation_builder() / summary_cards_builder() → UI rendering

Shared utilities:

calcs.core.electrical_utils.ComplexNumber — R+jX impedance class
calcs.core.electrical_utils.calculate_parallel_impedance() — parallel Z combination
calcs.core.electrical_utils.calculate_transformer_impedance() — Zt from nameplate

Developer Guide — Code Paths

Purpose	File	Key Function / Class
Conductor impedance	`calculations.py`	`calculate_conductor_impedance(csa, length, insulation_type)`
Table 8.2 check	`calculations.py`	`check_table_8_2(active_csa, breaker_rating, trip_multiplier, cable_resistance)`
Table B1 check	`calculations.py`	`check_table_b1(active_csa, breaker_rating, trip_multiplier, cable_length)`
Main entry	`calculations.py`	`calculate_earth_fault_loop_impedance(data)`
Validation	`component.py`	`EarthFaultLoopImpedanceCalculator.validate_parameters()`
Registration	`component.py`	`register_component(registry)`

Developer Guide — Testing

pytest calcs/test_c0034_earth_fault_loop_impedance.py -v

The worked examples on this page are generated from the MCP validation corpus (mcp_public/validation/cases/fe_calc_efli/) by python manage.py generate_help_examples --tool fe_calc_efli; calcs/test_help_examples.py fails when the committed fragment is stale.

Test coverage includes:

TestCalculateConductorImpedance — PVC/XLPE lookups, zero length, invalid CSA, magnitude
TestCheckTable82 — matching/non-matching rows, B/C/D curves, pass/fail
TestCheckTableB1 — matching/non-matching rows, B/C/D curves, pass/fail
TestCalculateEarthFaultLoopImpedance — basic, transformer, supplementary, compliance
TestCalculatorClass — validation, round-trip, registration

Active CSA (mm²)	CB Rating (A)	Max L — B Curve	Max L — C Curve	Max L — D Curve
1	6	170	91	55
1	10	102	55	33
1.5	10	153	82	49
1.5	16	96	51	31
2.5	16	160	85	51
2.5	20	128	68	41
4	20	126	67	40
4	32	98	52	31
6	40	90	48	29
10	50	117	62	37
16	63	142	76	45
16	80	112	59	36
25	80	124	66	40
25	100	99	53	32
35	100	159	85	51
35	125	127	68	41
50	125	198	106	63
50	160	155	83	51
70	160	235	126	75
70	200	188	100	60

Active CSA (mm²)	CB Rating (A)	Max L — B Curve	Max L — C Curve	Max L — D Curve
1	6	170	91	55
1	10	102	55	33
1.5	10	153	82	49
1.5	16	96	51	31
2.5	16	160	85	51
2.5	20	128	68	41
4	20	126	67	40
4	32	98	52	31
6	40	90	48	29
10	50	117	62	37
16	63	142	76	45
16	80	112	59	36
25	80	124	66	40
25	100	99	53	32
35	100	159	85	51
35	125	127	68	41
50	125	198	106	63
50	160	155	83	51
70	160	235	126	75
70	200	188	100	60

Active CSA (mm²)	CB Rating (A)	Max L — B Curve	Max L — C Curve	Max L — D Curve
1	6	170	91	55
1	10	102	55	33
1.5	10	153	82	49
1.5	16	96	51	31
2.5	16	160	85	51
2.5	20	128	68	41
4	20	126	67	40
4	32	98	52	31
6	40	90	48	29
10	50	117	62	37
16	63	142	76	45
16	80	112	59	36
25	80	124	66	40
25	100	99	53	32
35	100	159	85	51
35	125	127	68	41
50	125	198	106	63
50	160	155	83	51
70	160	235	126	75
70	200	188	100	60