Thoughts on this....

[Electroglow]

TT..

Incoming cable from supplier

Feeding a 3 bed average house

Tails are split and a feed is taken via SWA 25mm 2 core to a garage that has been converted into 2 little bedsits. There is a switched fuse with in 1m of the main cut out / fuse.

On the out side of the bedsits there is a large a box with a 5 way consumer unit. Rod is installed and connected to this cu.

2x 50a mcb with 16mm tails suppling the bedsits

Both bedsits are on rcd protected boards.

Now what are your thoughts in this I would be interested to know

Thanks

 

[Andy™]

the SWA must have RCD protection, and be earthed at the supply side

 

[Electroglow]

Yep so I would replace the switch fuse with a time delayed rcd.

But then some one I know who has been a spark for about 25 years said to me why would u use a rcd on SWA ?

 

[Andy™]

Yep so I would replace the switch fuse with a time delayed rcd. But then some one I know who has been a spark for about 25 years said to me why would u use a rcd on SWA ?

because regs state it must have RCD protection, and have done for a long time (probably more than 25 years)

 

[betty swollocks]

I'm inclined to say I would only rcd the swa IF there was access to that rcd by the person using the bedsit/s

Basically if the bedsits are rented out and the rcd trips will the person in the bedsit have 24/7 access to the house to enable the supply to be re-energised?

If the answers no then I wouldn't rcd it

 

[springcrocus]

^^ +1

 

[Electroglow]

Ummm ... True ... As there are 2 bedsits if a fault accounts the front end rcd will trip both bedsits.

Therefor both will have no power until resolved..

That's y I would put a time delayed rcd in.

 

[springcrocus]

Missed the TT bit. :Blushing

Being TT, the SWA must have protection but any time-delayed one would be fine for this. However, it still ought to be accessible to the tenants of the bedsits.

 

[Andy™]

I'm inclined to say I would only rcd the swa IF there was access to that rcd by the person using the bedsit/sBasically if the bedsits are rented out and the rcd trips will the person in the bedsit have 24/7 access to the house to enable the supply to be re-energised?

If the answers no then I wouldn't rcd it

you cant just ignore regs and not fit an RCD where required because there may not be access to re-set it

 

[betty swollocks]

I'm inclined to say I would only rcd the swa IF there was access to that rcd by the person using the bedsit/sBasically if the bedsits are rented out and the rcd trips will the person in the bedsit have 24/7 access to the house to enable the supply to be re-energised?

If the answers no then I wouldn't rcd it

you cant just ignore regs and not fit an RCD where required because there may not be access to re-set it

Your right Andy I never read the tt part and was simply thinking of inconvenience

Il thrash myself severely

 

[batty]

Its all about discrimination TD RCD mains end then standard RCD protection the other end.

 

[VoltzElectrical]

which regulation states that sub mains supply must be rcd protected? I'm not saying it's not true! I take this as an opportunity to learn a bit more about the regs.

Thanks

 

[Andy™]

which regulation states that sub mains supply must be rcd protected? I'm not saying it's not true! I take this as an opportunity to learn a bit more about the regs.Thanks

the one thats says all TT circutis need an RCD...

 

[VoltzElectrical]

but if each board had an rcd, then the sub main cable supplying them would not?

 

[Andy™]

but if each board had an rcd, then the sub main cable supplying them would not?

all wiring on TT must have an RCD. unless you can somehow guarantee a Zs low enough to operate breaker, which is unlikely

 

[VoltzElectrical]

ok cheers.

 

[SLIPSHOD & SLAPDASH]

[quote name='Andy

 

[Andy™]

So what if this installation was say 35 years old before the regs stated it ? I am not stiring things up but am intrigued as to peoples views on what should & what shouldn't be noted on a EICR (OK, very slightly off topic, but not really) .

probably C2, since its lacks any earth fault protection

and if it was 35 years older than requiring an RCD, then the wiring must be very old, since TT wiring has needed RCD'd for a long time

 

[SLIPSHOD & SLAPDASH]

I dont do many TT installs. When did the regs change to say some sort of Rcd is needed on a TT ? Was it a reg the old voltage operated earth leakage device's had to be fitted before this

---------- Post Auto-Merged at 22:05 ---------- Previous post was made at 21:57 ----------

Just found this old thread and thought its worth posting here again http://www.talk.electricianforum.co.uk/question-answer-board/9084-voltage-operated-earth-leakage-circuit-breaker-early-obsolete-type-rcd-whats-wrong-them.html

 

[steptoe]

I dont do many TT installs. When did the regs change to say some sort of Rcd is needed on a TT ? Was it a reg the old voltage operated earth leakage device's had to be fitted before this---------- Post Auto-Merged at 22:05 ---------- Previous post was made at 21:57 ----------

Just found this old thread and thought its worth posting here again http://www.talk.electricianforum.co.uk/question-answer-board/9084-voltage-operated-earth-leakage-circuit-breaker-early-obsolete-type-rcd-whats-wrong-them.html

very very good point Slips,

and a lot of different interpetations on this if I remember correctly,

I was always under the impressiopn, and told/instructed accordingly that if I ever came across a voltage trip (15th+) I was to ring the office immediately, we then issued a danger notice to the client and isolated the property, what he done afterwards was his decision, still is today.

I may be wildly wrong, but I will still issue an EDN and switch off a voltage trip.