230 volts drop off but nothing is tripping

PatEgan08

when i test a socket between live and neutral i get 230v but when i put a load on it i get 0v rcd and mcb are not tripping and i am still getting 230 between live and earth. can someone please come up with an answer please

davelerave

you might have bad connection on a neutral nearby (if its only a local problem).230v will drop across the high-impedance voltage tester but voltage will fall when a load is connected.

2011

Out of interest what do you get between neutral and earth when the load is connected?
Does the load draw a current when it is connected? (You can check this with a grip on ammeter)
What is the load? Is the load working as it should?

It sounds like you may have the volt meter connected incorrectly. It should be connected in parallel with the load, not in series with the load.

rcd and mcb are not tripping

There is no reason for them to operate. The MCB should only trip if there is a sustained over load or a short circuit condition. The RCD should only trip is there is a difference of more than 30mA between the currnet flowing down the live and the current flowing back on the neutral.

davelerave

on second thoughts. i wouldnt expect the voltage to drop to zero normally.anyway i'll wait to find out

PatEgan08

I am going to replace the cable as i have found a junction box
on it outside and it is not outdoor rated so then i will find out if its a bad connection. The load is a washing machine and is not working also tried a light bulb on a plug same thing happened. I knew the mcb and rcd shouldnt trip just didnt want people saying this was the problem.

davelerave

you would need voltage monitoring of some type in the connected equipment to protect against 'undervoltage'.Mcbs and rcds only cover fault current ,overcurrent and short-circuit as you prob already know

PatEgan08

Do you think sags or brownouts would harm the washing machine this much

davelerave

do you call 0v a brownout

PatEgan08

no i wouldnt call 0v a brownout but why do i need to protect against undervoltages if its 0v its not getting any voltage sorry but i havent had much experience with undervoltages this has me very confused. i didnt replace the cable yet but will let you know if it works.

2011

OK lets recap:

The load is not working, there is no voltage between L & N and there is 230 volts between L & E. The problem is that your neutral is broken.

What you have to do is find where the neutral is broken. I would say that there is a good chance that this is at the junction box.

davelerave

PatEgan08 wrote: »

no i wouldnt call 0v a brownout but why do i need to protect against undervoltages if its 0v its not getting any voltage sorry but i havent had much experience with undervoltages this has me very confused. i didnt replace the cable yet but will let you know if it works.

i didn't mean your specific machine needed protection.:D

PatEgan08

the neutral is not broken because i have 230v between live neutral until i plug in the washing machine never came across somethng like that before could be a faulty socket could be the junction box didnt get round to the house since but im replacing everything today everything should be fine then just wanted a few ideas why voltage was droppig to 0 very strange.

davelerave

check/ replace at socket anyhow first