Storage Heaters-TT System-No RCD

[CAWORK]

Hello

To settle a slight confusion/misunderstanding, could I just have some opinions on the following please:

Earth rod in garden, no sign of any main earth from cutout (overhead supply) therefore probably TT.

24 circuits 1996 installation 30mA RCD incomer in CU, 5 circuits.

Storage heaters with own CU installed about 2007 ordinary main switch and MCBs - no RCD protection (or MCB labelling etc) don't know about certification etc.

It had been suggested, that that you don't need to/shouldn't RCD storage heaters but don't all circuits in a TT install require RCD protection regardless of what the circuits are supplying?. It is planned to have a PIR carried out anyway though.

Also at least two houses a little up the road supplied from the same overhead lines have a PME system installed.

Regards

 

[electronicsuk]

Yes, all circuits should be RCD protected on a TT installation. At the time of installation it may have been permissible to have the storage heaters backed by a 100mA time delayed RCD, but they should still be protected nontheless. To current regs, it's very likely the whole lot would have to go on one or more 30mA RCDs, or each circuit have its own RCBO.

 

[LoveRocket]

Yes. In a TT installation every circuit needs RCDing at no more than 100mA - this is because the EFLI is so high that an MCB wouldn't trip even with a hard L-E fault.

 

[Taylortwocities]

. At the time of installation it may have been permissible to have the storage heaters backed by a 100mA time delayed RCD, but they should still be protected nontheless.

It wouldnt have needed a time delayed one, but that's academic.

Nothing wrong with a 30mA incomer on the off peak board. Its a single point of failure but not life threatening if all the heating goes off.
My gas boiler does it all the time!

 

[electronicsuk]

. At the time of installation it may have been permissible to have the storage heaters backed by a 100mA time delayed RCD, but they should still be protected nontheless.

It wouldnt have needed a time delayed one, but that's academic.

You are, of course, right. Of course, even an installation to the 16th would be likely to have at least some of the socket outlets (reasonably expected to supply outdoor equipment yadda yadda) on a 30mA RCD, so it would be unusual to see this combined with a non-delayed 100mA RCD, which would be unlikely to provide any discrimination.

 

[CAWORK]

Thanks for everybody's help


Regards