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]

id like to add that the testing of the circuit should have been done prior to changing the heater

 

[static zap]

With no power present , + trained same way staff
,could be a polarity issue ! ...eek

 

[elsparko]

With no power present , + trained same way staff
,could be a polarity issue ! ...eek

anything is possible with a 25metre r2 lead...

testing a dead circuit is easy, polarity would be a case of start at meter and work way back from point to point testing continuity

wouldnt surprise me if the meter has been changed recently though

 

[Dave OCD]

Does the heater run for a full continuous 7 hours on the 24 hour supply MCB without issues ?

 

[Steve Poulton]

Elsparko, really helpful mate. Testing on the E7 circuit revealed no faults. How does it works on the main unit when connected to that? Surely its the same circuit just wired into E7 MCB's. As posted the E7 MCB's work fine with the others night storage heaters in which ever MCB its placed into?

 

[Steve Poulton]

Dave OCD yes it does.

 

[elsparko]

Elsparko, really helpful mate. Testing on the E7 circuit revealed no faults. How does it works on the main unit when connected to that? Surely its the same circuit just wired into E7 MCB's. As posted the E7 MCB's work fine with the others night storage heaters in which ever MCB its placed into?

im going to have to re-read your post again

 

[Octopus]

Elsparko, really helpful mate. Testing on the E7 circuit revealed no faults. How does it works on the main unit when connected to that? Surely its the same circuit just wired into E7 MCB's. As posted the E7 MCB's work fine with the others night storage heaters in which ever MCB its placed into?

Based on what evidence? What tests? What results?

 

[KEV 1 N]

Are the mcbs in the E7, exactly the same as the normal DB?

 

[Dave OCD]

I think the only thing left is to rewire the circuit in question, can't be the heater.

 

[Octopus]

Its a new storage heater as the other one was old and it was thought that the problem was with the old heater. They haven't charged for the new heater as they want to fix the problem before they do. They are willing to return the old heater to avoid unnecessary expense as long as we can sort the problem. So in other words both heaters are tripping the E7 15amp MCB but not the normal board when connected to that.....

Hum .......... this puzzles me - the supplier of the new heater is suggesting you get somebody else to find the fault?

That is bizarre to say the least.

 

[KEV 1 N]

I would try and replace the mcb in the E7 DB for a new one, to see if that stays on. Providing the circuit has no faults

 

[Octopus]

I would try and replace the mcb in the E7 DB for a new one, to see if that stays on. Providing the circuit has no faults

The OP has suggested that this storage heater ijn particular trips any of the E7 MCB's .............. so if its not the MCB, or the heater it has to be the cable and / or connections between the 2!

 

[Dave OCD]

I did wonder that too, in particular I've had the older plug in Wylex 'retrofit' MCBs become very sensitive and even 'trip' when the sun heated the porch where they were !

 

[westward10]

Sounds like dead testing shows nothing. What ideally needs to happen is to throw a test on it immediately after it trips this can be done during the day if the electrician is confident enough to energise the E7. One random try is to replace the isolator at the heater, you never know.