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Flat electrical system update

Postby ovin » Tue Aug 14, 2007 11:17 pm

Hi I have a ground floor maisonette built in the late 1960's. The wiring is grey PVC stranded and is generally in good condition. My question is, can I update the fuse box (black hard plastic fuse type) with MCB/RCD's without having to replace all cabling for ringmain & lighting.
The property also has electric underfloor heating on economy seven (installed in the late 1960's). This has a seperate fuse box, & thermostats on wall in 4 rooms that all work but look dated, I would also like to update this system replacing the thermostats & install new fuse box.

Light swithces & roses have been renewed so have the power sockets which are below 450mm but have all been replaced with new faces.

The main fuse boxes do not have any way to isolate from main incoming cable from meter, there is also no isolation prior to the meters except a tagged fuse holder looking thing above the main incoming cable.

Is it common for electricians to work on these live to replace fuse box or does the power need to be de-energised via the electrical supply company beforehand?
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Postby stevenc1603 » Mon Nov 05, 2007 3:44 pm

I'd imagine that replacing the consumer unit is possible, but I don't know if there are any regulations against doing it with old wiring in place.

If there is no switch disconnector between the meter and the consumer unit then you would have to disconnect the supply (tagged) fuse. In some cases the tag is loose enough to allow you to pull it out and jam it by sticking in a bit wood to make sure it doesn't make contact again while the consumer unit is being worked on.

I don't imagine that there's anyone foolish enough to work the main feed live and to do so is against the law anyway but you never know.
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Postby kbrownie » Tue Nov 06, 2007 7:58 am

hi ovin, you can replace the old type fuses (know as either semi-enclosed or re-wireable fuses depending which ones you have) they both look alike.
No need to replace the whole fusebox you can buy mcbs that will slot in to the existing fusebox. I am surprised there is no isolation switch, the tagged fused should only be removed by your electrical supplier. You should really get an experienced electrician in. Replaceing fuseboxes and new cable installation is required to be notified to the council or be done by part p qualified sparky. Sorry to be a spoil sport but if this work is not done correctly and tested, you will not get the correct certificates and it could invalidate insurances and affect any sale of the property, and it's dangerous too if you don't have the knowledge on how to do these types of installations.
Regards and be safe.
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