RCD for TT system

[dazza69]

Hi all,

I have just read an old periodic report that has highlighted a TT system that has an RCD main switch mounted in a non insulated enclosure (metal) as a category 2.
Does it state anywhere in the reg that the RCD should be in an insulated (plastic) enclosure. I've had a look but cant find anything.

Thanks

D

 

[not clever]

531.4.1

 

[dazza69]

531.4.1

I thought that was refering to the use of class 2 equipment between the origin of the supply and the installed RCD.

 

[not clever]

I would consider the origin as the outgoing terminals of the distributor’s meter or isolating switch, not always possible to have an RCD located here on the tails.
So therefore load side & connected tails of the dist meter would not be the origin, but would be classed as the customers equipment (as in not the origin) & this is where you would find the single rcd.

Your meter tails will comply if they are insulated & sheathed.....but will the enclosure they enter ?
Consider a class I enclosure & any fault between the origin & the terminals of the rcd (tails in contact with the earthed Class I enclosure), thats right due to the probable high Ze on a TT system will mean the rcd will not detect the fault & the suppliers cutout will not dissconnect the fault leaving the Class I enclosure and all earthed metalwork in the installation at..........................the supply voltage potential.

Class II enclosure or the insulated bushes that keep the tails seperated.


Hows that for you

 

[dazza69]

Ok not clever, got it now thanks. That makes perfect sence. I just wish the regs were writen in english and not some strange language from a land far far away!!! Cheers.

 

[not clever]

No probs