Regs on isolating a DB and earthing conductor size

[normanton]

Just wanted to double check two regs.
1. Do you HAVE TO have a double pole switch between the cut out and the DB (so you can isolate the DB)
2. Do you HAVE TO have a 16mm earthing conductor alongside the 16mm tails (the load on the installation is no more than 5 amps ((teleco cabinet Virgin Media))

 

[telectrix]

1. no.

2. earthing conductor should be sized to be able to carry PEFC without damage.

 

[johnboy6083]

you must have a single point of isolation for the installation, but this can be the main switch of a DB or MCC, ir consumer unit. It doesnt have to be a standalone isolator, although in most cases that is preferable.
As far as im concerned no as long as the installation is not PME, you can size the earth as you would a CPC, that is either by calculation using the adiabatic or by selection from the BS7671 tables. The DNO may have caveats ect where they insist upon a minimum size of condcutor for the mains.

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tel beat me!!

 

[normanton]

It is a PME installation ..... So 16mm earthing conductor ? What Virgin are saying is that if maintenance is ever needed to be carried out in the DB, the only way to isolate it is by pulling the main cut out fuse ...

 

[Des 56]

It is a PME installation ..... So 16mm earthing conductor ? What Virgin are saying is that if maintenance is ever needed to be carried out in the DB, the only way to isolate it is by pulling the main cut out fuse ...

Well here is your chance to get Virgin to lobby the government for that isolator they wont be putting into the proposed smart meters

Virgin seem to be applying common sense,that will never do in this industry,but required to work on the board ? No

 

[normanton]

Yea that's true, ok thanks for that .