odd electrical fault

[ballyclover]

hi guys,

hope someone can help, i have a very odd question. My grandad bought a 1KW fan heater to use in his green house.He has a power supply in there which runs his drill and other equipment but will not run his heater. This is an extension lead ran from a 3pin plug in the shed,its 2 core not earthed. (i know this isnt legal but its been there years and we are going to replace it)

So into the shed, he has a mains cable coming from the house into the a little old fuse box,from this he has ran two double sockets, both earthed on the right hand side of the shed. Neither of these will run the heater,but both run drills etc. One of these has the extention to the green house plugged in.

Now for the odd part, one of the double sockets on the right hand side(which doesn have the 3 pin plug extension to the greenhouse in),has had another twin and core cable taken from it to create a single socket on the left, this powers the fridge. Now this socket works find with the heater.

I have used a mains tester and it shows 3 lights on all sockets which indicate ok


I do not understand why the two on the right wont work,but the one of the left which is bascially part of the same circuit will. To be honest its a nightmare set up in there and needs redoing, but can any shed any light on the problem.

would be appreciated.

 

[Space cat]

Have you looked inside the heater's plug? Maybe neutral and earth are crossed - meaning that it'll only work in a socket with an earth connection.

Even if the plug is wired correctly, the heater itself might not be. If you have access to an ohm meter, measure the resistance between each pair of pins on the plug. (Heater switched on off course.) You're looking for about 60 ohms between live and neutral but infinity (well many megohms at least) from either to earth.

 

[PrenticeBoyofDerry]

So the heater does work then?
Have you tried the heater on a socket circuit in the house?
It is strange that the drill works on the socket that the heater won't.
I think a little more investigation is needed!
Is the plug of the heater making good contact when plugged in, I have a garden extension lead that everything works fine on but when I plug my Makita SDS drill in to there is no power to the drill, the drill works fine on all other outlets, after a little head scratching I realised that the plug did not sit in the outlet very well and good connections were not being made.

I would also do a visually inspection on all internal connection of the socket outlets and the plugs of the equipment/extension lead.

 

[ballyclover]

yes, the heater works fine in the house and also in the left hand side of the shed.

the heater is brand new and as i say it works everywhere apart from these 3 sockets.

 

[securespark]

You have used a mains tester in the fridge socket & it shows all three lights.

What does it show when you plug it into the sockets in which the heater does not work?

 

[westie101]

Tch, tch

I have used a mains tester and it shows 3 lights on all sockets which indicate ok

 

[securespark]

That's all that ENWL guys use after working on a supply fault.

Get all three neons glowing and it's a pass as far as they're concerned.

 

[westie101]

Get all three neons glowing and it's a pass as far as they're concerned.

We do now use them as part of the process, and certainly not as the only means of proving polarity.
We have to confirm polarity on the main and the service cable, at the cutout and on all floors of a property.
We also have to confirm it before and after for planned work!

Following a fault if we cannot confirm polarity we are obliged to leave customer's with no supply until we can.

Obviously there is a weakness with these testers as they do not show an N/E cross, but with the other confirmations we must do that is not seen as an issue

 

[JohnW2]

We do now use them as part of the process, and certainly not as the only means of proving polarity .... Obviously there is a weakness with these testers as they do not show an N/E cross, but with the other confirmations we must do that is not seen as an issue

I am struggling with the concept of a 'N-E cross/reversal' on your side of the meter!

Kind Regards, John.

 

[ballyclover]

sorry for the late reply. all 3 lights are on, on all 3 sockets on the tester.

still doesnt work, only thing i would say is that the soxket that supplies the fridge is a newer single socket where as the ones that do not work are old double sockets, maybe thats the problem

 

[Space cat]

Since the heater is brand new, its plug will have insulation half way to the ends of its live and neutral pins. Older plugs had plain brass pins without this insulation. Have a look at all the things that do work in those two old sockets. What kind of plugs do they have?