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The Table 41.1 rule, and where to look in BS 7671Which circuits does Table 41.1 cover?
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Where to look in BS 7671
This topic generates a lot of questions. The confusion is all in Chapter 41 of BS 7671 (protection against electric shock), where there are several different maximum disconnection times. The aim is to know which one applies to the circuit in front of you. Have your BS 7671 open around pages 71 and 72.
BS 7671 · Chapter 41 · Regulation 411.3.2.2 (which circuits use Table 41.1) · p.71 BS 7671 · Table 41.1 maximum disconnection times · p.72
BS 7671 · Regulations 411.3.2.3 (TN) and 411.3.2.4 (TT) · p.72 Have these two pages open for this whole masterclass
The Table 41.1 rule
Regulation 411.3.2.2 says the maximum disconnection times in Table 41.1 apply to final circuits with a rated current not exceeding:
- 63 A or less, with one or more socket-outlets
- 32 A or less, supplying only fixed connected current-using equipment (a shower, a cooker, a heater…)
Turn that round, and you get the three cases where you don't use Table 41.1:
- The circuit isn't a final circuit (it's a distribution circuit, feeding another board).
- It's a final circuit supplying sockets above 63 A.
- It's a final circuit supplying fixed equipment above 32 A.
Keep saying it to yourself: Table 41.1 = final circuits, sockets up to 63 A, fixed equipment up to 32 A. Everything else goes to the two regulations that follow it.
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