300va wiring PLEASE HELP!!!!

[ban-all-sheds]

Different part of the house- for some reason he's put 4mm in one area and then 2.5mm in another - both are for the same type of light fitting???

Not sure why he's done this

He's done it because he is an incompetent ***t.

I have UFH going in next week which will cover up all the remaining cables. It will be very difficult for a new sparky to see what he has done!

You must put the UFH on hold - it's not just a case of a new electrician seeing what's there, it may also need changing.

I am concerned that he doesn't know what he's doing and that fixing it with a new sparky is going to cost me a fortune!

He doesn't, and it is going to cost.

You should take legal advice, you should get a report done by someone who could be an expert witness if needed, and you should gird your loins for taking the incompetent ***t to court.

Is it possible to notify BC at this stage and do second fix myself?

No.

 

[crunchynut]

The lights will be dimmer than they should be, as they are not getting 12V, more like 10.6V

Relating to this I recently went to look at a dodgy tranny (no, not that type!), the halogen was equally as bright as other lamps but was only getting 7V through to it. Measured it with 3 different meters! i thought it would be much dimmer also.

 

[bexxxxx]

oh - OK - that makes me feel much better!

 

[crunchynut]

The lights will be dimmer than they should be, as they are not getting 12V, more like 10.6V

Relating to this I recently went to look at a dodgy tranny (no, not that type!), the halogen was equally as bright as other lamps but was only getting 7V through to it. Measured it with 3 different meters! i thought it would be much dimmer also.

 

[bernardgreen]

but was only getting 7V through to it. Measured it with 3 different meters! i thought it would be much dimmer also.

Most multimeters will give an incorrect reading of an AC voltage coming out of a switched mode power supply as they are calibrated to read the RMS value of a sine wave at 50 Hz. The chopped / pulse width / high frequency voltage on the output of an electronic "transformer" has a waveform that the common meter is not designed to measure.

 

[crunchynut]

Never thought of that Bernard. It does make sense.

The meters were two cheap jobbies and a Megger mft1552 which I got out of van due to the cheapo multi meter readings. Tried another tranny and it measured near to 12V so am a lil confused as to why lamp wasn't dimmer than the rest.

Cheers.

 

[ban-all-sheds]

If it really was only getting 7V it would have been very dim:

 

[Stoday]

Very dim? Power is proportionasl to the square of the voltage, so reducing the voltage from 12 to 7 volts would reduce the power to 34% of the original.

That assumes that the filiament resistance remains the same. It does not; it falls as its temperature decreases That means that the power to the filiament is not proportional to the square of the voltage but to some lesser exponent.

Maybe that means that the lamp becomes dim rather than very dim.