Rcd protecting new ring main

[davek]

Hi all,
I have been to look at a job, in a unit who require extra socket in a office. It is one of those building that has been split into small units,
The supply is 3ph. Each unit is supplied from mains with separate meters and a 3pole isolation switch with bs88 fuse 63a.
the board is a merlin gerin isobar 4c. the breaker are c60hb. my thought where rcbo but I can only get a c rated 32a which using table b6 gives me 0.58 ohms the zs at supply to board is 0.18.any thought or suggestions.
thanks
Dave

 

[shanky887614]

Re: Rcd prottecting new ring main

was just sort of adding up 5 meters plus 7 drops averaging 4.5 mts per drop plus the 10 meter for run to room possibly 50 meters total cable for ring

buy a copy of the "onsite guide"

they recommend max of 100m for 2.5 ring mate or 50m for a radial. more load or longer distance go for 4mm etc,
why is it a concern?


and why not use a b type rcbo?

 

[bigdavs83]

I would it fail it because of the manufacturers recommendations! Not rocket science that. Now we all know that a hager breaker is not gonna blow up as soon as as it is fitted in any different type of db to which it can be fitted. Should it go pear shaped tho it's your door they are chapping. Anytime I see it any of the commercial dbs I come across I report as a fail. You've got a nice 76 way board and one breaker is completely different from the rest! Looks guff and has in the past failed insurance audits. During PIR tests our testing guys will always pick it up as non compliant.

 

[bigdavs83]

72 way even!! Whoops

 

[Guest77]

72 way even!! Whoops

Yes I get your point, more leg pulling than arguing fella :biggrin:

 

[Plonker 3]

But you cant fail a PIR anymore as they no longer exisist. Can you show me a copy of any MI thats shoes only OCPDs of a certain type can be fitted to a certain board and what the consequences will be if you dont?

 

[Plonker 3]

What code would you give it now on a EICR?

 

[Guest77]

What code would you give it now on a EICR?

A code 1, it is dangerous lol

 

[telectrix]

A code 1, it is dangerous lol

only if you fit it upside down.