is it permissible to use 30ma rcd on a tt system as main switch as part of 5way c.u......thanks men 
tt system
- Thread starter seehig
- Start date
K
kai
It depends on the EFLI, it can sometimes be as high as 1666 ohms, in which case a 30mA RCD must be used, to keep the touch voltage down below 50 volts.
The normal way to do it would be to fit a 100mA time delayed RCD as the main switch, and then an additional standard 30mA RCD / RCBO to any circuits which require additional protection (such as socket circuits likely to supply equipment outside)
wouldnt it be better to use a 100a main switch then a split load cu?
Isn't that what I said?
barely and not allowed at all if you have mains powered fire alarms (possibbly just ones without battery backup i'm not sure on the details of fire alarm regs.seehig said:is it permissible to use 30ma rcd on a tt system as main switch as part of 5way c.u......thanks men
No - you said 100amp 100mA RCD 
BS is confusing a TT for PME or isn't expanding on his ides...
hell.
can't write straight
BS is confusing a TT for PME or isn't expanding on his ides...
hell.
can't write straight
Ah I mis read BSs post as "wouldnt it be better to use a 100mA main switch then a split load cu"
So in reply then, No it wouldnt be better to use a 100a main switch then a split load cu, as the OP is about a TT supply.
So in reply then, No it wouldnt be better to use a 100a main switch then a split load cu, as the OP is about a TT supply.
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