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jda19780 · Joined: 13 Aug 2006 Posts: 12 Location: Durham

I am thinking about having my old cartridge fuse box replaced with a consumer unit with trip switches. Can anyone advise please how involved this is in the light of new regulations and earthing practices. What would be the expected charge to have this done?

Thanks
JDA

vince knight · Posted: Sun Aug 12, 2007 6:25 pm Post subject:

It all depends on the age of the installation.
If you have no earths in you lighting circuit or no main bonding then this would need to be rectified first.
All works would need to carried out by a part p registered electrician or firm.

Vince

jda19780 · Joined: 13 Aug 2006 Posts: 12 Location: Durham

Thaks Vince. The house is 37 years old and there is earth strapping to the rising main and gas meter Don't know about lighting. My understanding is that the earth bonding has to be of a higher gauge now - 10mm? If this earthing need upgrading does that mean that it has to be linked between the incoming electricity supply point and the rising main or could it just be fixed to any water pipe below the floor. My concern is - that to refix to the rising main would involve taking up a tiled floor. I know it is difficult to say but in a straightforward upgrade what would I expect to pay.
Thanks.

vince knight · Posted: Mon Aug 13, 2007 2:51 pm Post subject:

With no further works you would expect to pay between £200 and £250 +VAT that would also include certification with the council.

The main bond size will depend on the incoming fuse size but 10mm in the min.
10mm would also need to be taken to within 600mm of the isolation valves for the water and gas services(or where they enter your dwelling).

Vince

thomas · Joined: 24 Sep 2007 Posts: 6 Location: NEWPORT

With regard to the consumer unit .. considering all wiring checks are ok earth bonding etcs .... you could replace the wired fuses with mcb,s which are supplied with bases that will fit the old wylex units...(cost about £8 each) it means disconnection of the old circuit and reconnecting into the new mcb base............. this must be done by a qualified elect but would save you the price of installing a complete new unit!!

A separate rccb (earth fault ) could also be fitted

Just did this job myself no problem and passed inspection..cost £90

Oldie Sparkie

vince knight · Posted: Fri Sep 28, 2007 3:05 pm Post subject:

The retrofit Wylex MCB's do not require the wiring to be touched. It is just a case of swapping the rewirable bases and then plugging in the correct rated MCB.
As long as the main switch is off, this could be done by a competent diy-er.
The installation of an RCD would require the main tails being split so would need to be done by a registered electrician.

Vince

thomas · Joined: 24 Sep 2007 Posts: 6 Location: NEWPORT

Vince .. would you spend money on a rccb if the system is PME???

vince knight · Posted: Sat Sep 29, 2007 8:43 am Post subject:

It depends on how good the Ze was, but yes I would to provide supplimentry protection.
I had a Ze on a PME a couple of weeks ago that read 1.02 ohm Exclamation

Called in EDF to rectify.

Vince

thomas · Joined: 24 Sep 2007 Posts: 6 Location: NEWPORT

How about an existing consumer unit with split b/bars with lighting circuits unprotected by the main rccb on the unit ...would it be necessary to add another rccb to reach inspection standards??

vince knight · Posted: Mon Oct 01, 2007 5:33 pm Post subject:

Only if it was on a TT(overhead) supply.
I would fit a 100ma time delay rcd to the incoming tails and leave the 30ma to protect the socket circuits on the split load board for supplimentary protection.

Vince