Voltage dropping in a domestic house as you use more appliances ?

[R G]

Sounds like a neutral fault , High resistance Neutral and the lower voltage you're getting could be the resistance using the earth path through the bonding in the property , so you may have no neutral at all and the bonding is the return path , so therefore the RCD is not picking up any imbalance , this is not good and supply should be isolated immediately and supply co informed ..

As a means of checking isolate the supply at the main switch and disconnect the main cpc and check with test leads & volt meter

 

[Darkwood]

Look under the busbar rail at the clamp positions of the busbar pins for the main switch and the socket circuit plus the rcd's ... it could be you have got a pin on the wrong side of the clamp and adding load drops the voltage due to a poor connection .... This will show good voltage until you add load.

Also see when loaded if a VD exists between N/E - this would suggest a loose N.

Load the circuit up and see how far upstream the voltage drop is... if its at the incoming terminals of the DB directly connected to the meter then it is likely a DNO issue but double check by putting you meter probes on the copper of the incoming cable as sometimes the terminals have a anti-corrosion wax on them than can give misleading readings.

PS sorry for the urine take earlier... but you want to be careful where in your opening post you actually ask for the help

 

[Sailbadthesinnr]

Some RCDs are not meant to be tested directly on the terminals, make up a short test lead and try again with that.

?? Can you explain why that would make any difference ??

Thanks.

 

[Malcolm]

Had something similar the other day.
Called out at 8.45pm, customer said "there is power coming into the house but nothing working in the house!!??"
Got there, house pitch black.
Got a reading of 110v across L/N, put a fuse in it dropped down to zero.
Called out DNO turned out to be a fault in the pre paid meter.
Never had that one before.