old wylex board, blown fuse

Shaun12 · Jun 16, 2015

My girlfriends stepdad replaced an old light fitting for a new one and blew the fuse. It was connected to an old re-wireable 5a wylex fuse. It's an old 1960's house wired in singles. Non of the cables are identified. At first glance i presumed he had connected the switch wire into the neutral terminal with one other neutral and in the live terminal he had put a neutral. Would this blow the fuse?

I replaced the blown fuse with a wylex mcb type breaker. left the wiring as he had it but removed the light fitting and placed the cables in a connector. Turned the power on, all was ok the breaker held.

I then turned the power off and out of curiosity belled the cables out(well the switch wire) the sw was connected with a neutral. So i've removed the sw and placed it in the live terminal and taken the cable out of there, which must be a neutral and paired it up with the other cable which must also be a neutral. Turned the power on an all is fine.

ifindoubtdont · Jun 18, 2015

There are a lot of assumptions in your post. I would first check the ceiling rose and correctly do a continuity test on the cables, swopping cables around and thinking it must be right cos it didn't trip anything is not the right way to go. I note your last sentence refers to a "Bang Test". Turned the power on and all is fine!. It didn't go Bang so it must be OK. Check it out properly, oh, and don't touch the taps.

Shaun12 · Jun 18, 2015

I checked continuity from the switch to the light, to find the sw. As it's wired in singles the live goes in and out at the switch. I admit the two other cables at the light fitting have not been checked for continuity, they are neutrals in and out though. There are no earths at the fitting or switch. I don't know if this is due to the age of the wiring and this was how it was done in the 70's or the Cowboys have been in. Does this mean it needs a complete rewire?

Darkwood · Jun 19, 2015

If you lighting has no earthing then yes its due for a rewire for practical safety reasons, if you have any metal fittings or switches that require an earth then I suggest you remove them and fit plastic drops and switches or any kind of class II fitting that doesn't require an earth, if the lighting is like this then it brings in the question about the rest of the install and yes! up to the 70's it was common to wire lighting with no earth or tapped earths of pipe work.

If this is rented then the landlord is not holding up to his responsibility of maintaining the condition and safety of the Electrics, If its your own house then as an homeowner you should maintain you building as it ages and keep it safe whether it be the roofing, plumbing, electric etc ... so start saving up if its your girlfreinds property.

telectrix · Jun 19, 2015

if it's wired in singles, then it may be in metal conduit, which conduit could be the earth, or cpc as we now call it. if you post your location , one of us may be close enough to pop round with the appropriate test gear to check it. guesswork is not an option.