Old Wylex Fuse Board

[Allan29]

I have an old Wylex Fuse Board installed in 1970. It has never been changed because there have never been any extensions/modifications of any note. A recent lighting fuse failure (caused by the demise of a CFL, not a wiring problem) made me look into MCB replacements for my fuse holders.

I have just received some Wylex MCBs via EBay, marketed specifically for peope who want to change from fuses to MCBs, but the pin spacing is quite different, around 23mm instead of the 35mm for my existing fuse holders.

Is it possible to source MCB's for my style of Fuse Board?

Allan

 

[Chri5]

Not sure of your CU- would need a picture of it to confirm.

Would these be suitable? >

http://www.tlc-direct.co.uk/Main_Index/Consumer_Units_Index/Wylex_Standard_Range/index.html

 

[Allan29]

Yes Chrii5 they would be. Apologies but I realise I have overlooked the obvious. My MCBs came with matching bases which I assumed would be redundant. However, it looks as though I can remove the existing bases and replace them with the newly supplied ones, and all will be well. This would imply that the contact receptacles behind the bases are wide enough to accept either the fuse holders or the MCBs. I will have a look when it is convenient to switch off?

Allan

 

[TheOriginalTonkaToy]

Do remember that if you remove the protective covers there will be supply voltages present that are only protected by the main fuse which could be rated as high as 100A. Ensure you switch off at the main switch and be aware that the incoming supply to that switch will still be present.

 

[ricicle]

This is notifiable work as you are changing the circuit protective devices.

 

[Allan29]

Thanks to the replies here. I have now installed the lighting MCB and all seems to be OK, Yes I did switch off the main switch before swapping the base. I was also aware that this was notifiable work. I will probably do no more for the moment as it was the need to rewire the lighting fuse which was most inconvenient. As far as I recall, that is the only one that has ever blown before in the 30years we have been here, and it is always when a lamp fails.

Allan

 

[Chri5]

Allan it might be an idea to get a sparks to do a periodical inspection report.

This gives you an inspection and test record for the property, I'm sure the work you have done is better than it was, but how will you know if the MCB's work without testing each circuit?

 

[Allan29]

Yes Chri5, I probably should do as you say. However, I suspect that many electricians might look at my 1970s installation and insist that I upgrade and even rewire? For the moment, I have tested the 6A MCB 'on the bench' at 8.5A (2kW) or 1.42 times rating and it switched out after 56sec; good for 'B' curve. Clearly, this does not test the magnetic trip but suggests all is probably well.

I will leave the fuses in place for the other circuits for the time being as a blown fuse here is a lot less of a bother than the lights going out, and needing fuse wire, etc.

As a matter of interest, what would an electrician do to check the operation of MCBs in situ; just place a short across or a measured excess current?

Allan

 

[Adam_151]

As a matter of interest, what would an electrician do to check the operation of MCBs in situ; just place a short across or a measured excess current?

Allan

MCBs are very rarely tested in service, if there is doubt about a particular MCB then it should be replaced. If for some reason there is reason to need to test operation of MCBs, then there is a piece of kit called an current injection tester, but this is highly specialised and would likely involve a specalist company....

Its simply not going to happen in a domestic... or even the vast majority of commercial/industrial installations