RCDs on TT
- Thread starter xr4x4
- Start date
You don't need one if all of the final circuits are protected with 30mA RCDs or RCBOs. Conversely, if you have any final circuits which are not so protected, you need a 100 mA time-dayed ('Type S') RCD, in an insulated enclosure, prior to your consumer unit(s).
Kind Regards, John.
You need an RCD rated to ensure that disconnection will occur under earth fault conditions in such circumstances as disconnection times will not otherwise be met by the protective devices. This will be in most circumstances in a TT system.
Ok, thanks.
If you have a tnc or tncs with a metal CU the 30ma rcd can be inside the CU, with none outside.
But with TT, the install has to be protected with a external 100 ma type s rcd, if metal CU.
So I'm guessing basically with TT anything metal not rcd protected needs type s 100 ma protection?
If you have a tnc or tncs with a metal CU the 30ma rcd can be inside the CU, with none outside.
But with TT, the install has to be protected with a external 100 ma type s rcd, if metal CU.
So I'm guessing basically with TT anything metal not rcd protected needs type s 100 ma protection?
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