Totally stumped. Night Storage Heater tripping out MCB, but ok on daytime circuit.

[Steve Poulton]

Please help. I have a basic understanding of electirics, but 5 Electricians are stumped and I don't know where to go next. My mother in law heats her house by 4 Night Storage Heaters, all of which are wired to a Economy 7 supply/fuse board, with no RCD just MCB. The largest of the Night Storage Heaters began to fail and trip the MCD. To cut a long story short, she ended up having a new one fitted. Unfortunately this new one also now trips the MCB. The electricians have tried swapping the various supplies to the various heaters around in the E7 fuse board and the same heater is tripping the different MCB. It would be an obvious thing to consider that there is a fault on the circuit between the board and the night storage heater. However, they have now wired it into the day time board and it is not tripping. Has anyone got any ideas as we need to get it wired back into the E7 circuit??

 

[elsparko]

i would swap this job for the difficulty i had on monday drilling through a granite load bearing wall for a bloody smoke alarm, wall paper walls, and wallpapered roofs , no access above, other side of wall was coving!

one of the few jobs where trunking was the solution

 

[Darkwood]

i still dont see why the e7 supply needs to be live for testing, when it can easily be connected to the 24h , 6am start seems unreasonable

As hinted at the E7 supply itself could be at issue upstream of the MCB, swapping it out would hide the problem further, be interesting to get some readings off live testing.
6am start early lol... thought you Scots were made of stronger stuff

 

[elsparko]

As hinted at the E7 supply itself could be at issue upstream of the MCB, swapping it out would hide the problem further, be interesting to get some readings off live testing.
6am start early lol... thought you Scots were made of stronger stuff

if the fault is on the e7 supply itself then shirley all the heaters would fail?

 

[Darkwood]

if the fault is on the e7 supply itself then shirley all the heaters would fail?

I'm not called Shirley ....
-not necessarily, the effected mcb may have the heaviest load thus arcing of the L or N would create a larger transient on the heaviest load, it is not usually an issue with resistive loads so it may be a long shot but not something I would rule out without checking.

 

[LT21]

Fault found

Fault is with BSEN60947-3 100amp main switch arcing live conductor

While testing incoming voltage with multimeter I had clamp meter on out going supply

Voltage fluctuating between 235v and 210v resulting in outgoing supply to heater going up and down between 13 and 16amp causing MCB to overheat

There were no visible signs of overheating on MCB or main switch I broke Main switch apart see photo

 

[buzzlightyear]

will done LT21,if that had been done in the beginning then it would not be a 6th visit would it not .

 

[LT21]

Turn of events for 5 visits

1 visit
Call out storage heater not working
Tested storage heater and circuit found to be fault with circuit live to earth dead short
(Electrician 1)

2 visit
Install new supply to existing storage heater
(Deakon)
Storage heater worked for 4 days

3 visit
Tripped next day tested circuit and storage heater no fault found Presumed storage heater glitch ( cold damp Etc ) reset MCB ( Deakon)

4 visit
Tripped next day tested circuit ran temp supply to storage heater worked ok for 1 hour
Deakon wrongly diagnosed fault must be with heater ( we have all made miskates )

5 visit
Replace storage heater
Deakon

6vist
Test E7 incoming supply when E7 fault found
( Me )

I don’t think this turn of events is unreasonable for 6 visits granted on the 4th more investigation could have been done
But with E7 you are limited to what you can do with testing

I understand why the customers son in law came to you for advise ( Steve ) after 5 visits and I only came on here after he told me about all the negative comments and slagging off that was being targeted towards us as a company most off the comments were a load of rubbish

 

[Deleted account]

Well done.
That one would have had me stumped too.

It was a set of bizarre issues that I have learnt from and will remember if ever I get an issue like this.

I think the customer should be pleased with the determination to find and rectify the issue.

Some would have taken the money and run. You are obviously a professional with a reputation to keep.

 

[buzzlightyear]

I understand why the customers son in law came to you for advise ( Steve ) after 5 visits and I only came on here after he told me about all the negative comments and slagging off that was being targeted towards us as a company most off the comments were a load of rubbish

stick they head in a lions mouth ,what do you get!!!!!

 

[polo1]

Glad you found it, and as several had said, an unusual problem which would have stumped many electricians on initial investigation.
Good too that we all get to find out the source of the problem - another possible issue to add to our list of “ it might be.....”!

 

[Octopus]

Good feedback,.

There were aspects of this that didn't add up as outlined in the op.

Every day is a learning day

 

[Octopus]

I understand why the customers son in law came to you for advise ( Steve ) after 5 visits and I only came on here after he told me about all the negative comments and slagging off that was being targeted towards us as a company most off the comments were a load of rubbish

You've got to agree that the op didn't really help your corner by not answering key questions.

What make of board was it, and roughly how old?

 

[LT21]

Denmans special
10 year at a guess

 

[Squid]

I was going to suggest fitting a gas boiler and rads.................

 

[static zap]

Thankyou for sharing. (LT21)