Circuit Showing 97 Volts

[Jersey Cream]

Hi All, I was hoping someone might be kind enough to offer some advice please.

We moved to a new house and got rid of an old bathroom cabinet with a light above it. I’ve just got around to fitting a new cabinet and separate wall light. I’m not sure if the old light worked as it didn’t have any bulbs in it.

Having wired in the new light the led bulbs that I put in were very dim. I thought I’d just bought some poor quality ones so ordered replacements. They arrived but still dull! I tested the fitting with a volt meter and got a reading of only 97 volts. I took the fitting down and checked the connections. Both looked fine. Checked the switch no loose connections there either.
I Swapped the l1 from the mirror switch with a neighbouring switch one. The voltage across the one that I moved the mirror cable to dropped to 97 volts and the one the mirror light had used went up to 240 volts so I don’t think it’s the switch. They have linked common wires.

There is a permanent live to the fitting so I swapped the existing l1 wire for that. This made the lights work perfectly and brought the voltage up to 240.


I then decided to remove the l1 from the switch and replace it with the permanent live feeding the mirror light with a view to making it work on the switch. Having done that, the voltage dropped back to 97 and the mirror lights went dim again. It doesn’t take much but I’m baffled! Would anyone be kind enough to suggest anything else I might try please? Many thanks.

 

[333rocky333]

Sounds like a classic case of a Neutral somewhere connected wrong, therefore putting the light in series with another light, have you noticed any other lights dim with the new lamps in, or go off when just one of the new lamps are removed

 

[ericmark]

Standard ceiling rose 4 connections, switched line, permanent line, neutral and an earth tag. but often the switched line is a black or blue wire which should be sleeved brown or red, often the sleeve is missing and the black neutral and the black switched line get mixed up, this is a common cause.

The other is some one trying to connect up another lamp from the switch, and again switched line is used instead of neutral.

 

[Jersey Cream]

Thanks, Both. Very kind of you to come back to me - especially so late. I haven’t noticed any other lights behaving strangely but there is another new light on a neighbouring switch so I’ll try disconnecting that and see if it makes a difference. I did check the switch the other new light was connected to (and the others on the same panel) and there was 240v across each of them.

 

[Jersey Cream]

“Standard ceiling rose 4 connections, switched line, permanent line, neutral and an earth tag. but often the switched line is a black or blue wire which should be sleeved brown or red, often the sleeve is missing and the black neutral and the black switched line get mixed up, this is a common cause.”

In this case I’ve got four wires. Brown, Blue, Grey and the sleeved earth. The grey seems to be the permanent line. I was expecting to connect the brown and the blue to the fitting (which caused the low voltage) and I’m now using the grey and blue (which works properly but isn’t switched).

The other is some one trying to connect up another lamp from the switch, and again switched line is used instead of neutral.

There is only the one lamp coming from the switch.


I’m out of things to try now so I’ve messaged my electrician. I’ll post the solution when he finds it. Thanks again for your advice.

Read more: https://www.diynot.com/diy/threads/circuit-showing-97-volts.562835/#ixzz6ksFdjTaJ