EIT Tables 5-8, 5-43 to 5-46

Correction Factors

Multiply the tabulated ampacity by every factor that applies: Iz = It · Ca · Cg. Air tables are based on 40 °C ambient; underground tables on 30 °C ground.

Table 5-43 — Ambient temperature in air (base 40 °C)

Ambient (°C)	PVC	XLPE / EPR
11–15	1.34	1.23
16–20	1.29	1.19
21–25	1.22	1.14
26–30	1.15	1.10
31–35	1.08	1.05
36–40	1.00	1.00
41–45	0.91	0.96
46–50	0.82	0.90
51–55	0.70	0.84
56–60	0.57	0.78
61–65	–	0.71
66–70	–	0.64
71–75	–	0.55
76–80	–	0.45

Table 5-44 — Ground temperature (base 30 °C)

Ground (°C)	PVC	XLPE / EPR
11–15	1.18	1.12
16–20	1.12	1.08
21–25	1.07	1.03
26–30	1.00	1.00
31–35	0.94	0.96
36–40	0.87	0.91
41–45	0.80	0.86
46–50	0.71	0.82
51–55	0.62	0.76
56–60	0.51	0.70
61–65	–	0.65
66–70	–	0.57
71–75	–	0.49
76–80	–	0.41

Table 5-8 — Circuits in one raceway

Circuits	Factor
1	1.00
2	0.80
3	0.70
4	0.65
5	0.60
6	0.57
7	0.54
8	0.52
9	0.50
10–12	0.45
13–16	0.41
17–20	0.38

Table 5-45 — Direct-buried circuits side by side

Circuits	Touching	One diameter	125 mm	250 mm	500 mm
2	0.75	0.80	0.85	0.90	0.90
3	0.65	0.70	0.75	0.80	0.85
4	0.60	0.60	0.70	0.75	0.80
5	0.55	0.55	0.65	0.70	0.80
6	0.50	0.55	0.60	0.70	0.80

Table 5-46 — Buried conduits side by side

Conduits	Touching	250 mm	500 mm	1000 mm
2	0.85	0.90	0.95	0.95
3	0.75	0.85	0.90	0.95
4	0.70	0.80	0.85	0.90
5	0.65	0.80	0.85	0.90
6	0.60	0.80	0.80	0.90

Cable tray grouping (Tables 5-40 and 5-41) depends on tray type, arrangement and the number of trays — the Cable Sizing calculator applies it for group 7.

Source: EIT 2001-56 Tables 5-8, 5-43, 5-44, 5-45 and 5-46. Verify against the edition that governs your project before design use.