Correct Type-S Upfront RCD for 3Ph TT System

[Risteard]

All fusebox RCBOs are now switched neutral. I don't think they make any other kind now.

Only the compact ones.

 

[suffolkspark]

So I will use something like this (found a type A time delay) which I will put in a separate enclosure to replace that 100A isolator.

100A 4 Pole 100mA Type A Time Delay RCD

Test button

www.cef.co.uk

If those fusebox rcbos aren't switched neutral your gonna have a problem....

The tails appear to all be visible there so I wouldn't add upfront rcd protection to anything other than the submain going off to the kitchen.

 

[westward10]

If the supply conductors enter an all insulated enclosure then fault protection is not required.

 

[Raptor0014]

If those fusebox rcbos aren't switched neutral your gonna have a problem....

The tails appear to all be visible there so I wouldn't add upfront rcd protection to anything other than the submain going off to the kitchen.

They are definitely DP as they're the mini ones.

I'm a little confused as to why you say a upfront for the whole system isn't required? I was led to believe when I did my course (granted I think 'guru graham' as I used to call him was good at passing off his thoughts as a regulation sometimes) that on a TT it must have upfront RCD to protect the tails regardless.

I need to make sure this one has no hiccups as it will be looked at by my CPS assessor so that I can pay for the privilege of being a member for another year....

So I am not questioning your judgement. I just need to know how that fits into the regs as my understanding is its a no ifs, buts or maybes. But could be the way I've had it explained.

 

[westward10]

Why do you think they need rcd protection.

 

[Raptor0014]

The way I had it explained was that if a fault occurred between the tails and the board then it wouldn't be picked up by the RCD's in the board.

 

[westward10]

What type of fault.

 

[nicebutdim]

The full height are

Just did so quick research and can find nothing to suggest Fusebox have made full height RCBOs that switch both poles. Their new AFDD RCBOs are tall and switch both poles.

 

[Raptor0014]

What type of fault.

Line to earth

 

[Raptor0014]

Just did so quick research and can find nothing to suggest Fusebox have made full height RCBOs that switch both poles. Their new AFDD RCBOs are tall and switch both poles.

Yeah I think I have gotten it confused with the mini ones and the AFDD ones I was quoting for the other day (some bloke wanted all 14 circuits protected with AFDD! Soon changed his mind when I told him that was £1750 before we even started on the remaining materials and labour etc)