Electrician Jobs Problem with 11KW Kiln in domestic setting

[Sally Mills]

Can you clever people advise as to why I might be having an issue with my ceramic kiln. I am a potter not an electrician so I will endeavour to give you what technical information I have.

11kw kiln running off a domestic board with its own 50A fuse on board in the house, 15m lenght of 10mm cable runs from house into my studio where it has its own board with a 62A breaker and 50A fuse.

The fuse in house is tripping when firing cycle reaches about 1060 degrees (kiln should reach 1250 degrees). It used to reach 1180 degrees before tripping but over a few years it has been tripping earlier and early.

The firing cycle of the kiln goes up slowly, automatically over 5 hrs automatically turning on and off until the end when its on full load. Kiln fired fine with no tripping day before yesterday (post element change) when taken fast at full load to temperature, but when I did a slower firing last night it tripped.

Kiln engineer took a reading of 45Amp and there is a drop in voltage from 240 to 232 when under load.

I have had kiln serviced and elements replaced this week and tripping still happening so pretty certain its not the kiln.

Questions: Can anyone see an issue with the electric maths? Is the cable thick enough? Can a domestic fuse be upped to next level? Can cables get tired and old?

Any advise as to what to try next would be greatly appreciated as I'm soooo frustrated with this ongoing issue.

Cheers lovelies!

 

[LeeH]

What sort of ‘fuse’ is it. Is it a circuit breaker MCB, RCD or a combination.

Things ‘trip’ due to earth leakage and over current.

I would have pointed towards the elements leaking as the temp rises but if they are new it’s unlikely.

Keep in mind you will have a control circuit that operates the Kiln so it’s possible to have a faults in that.

Pretty hard to diagnose without being there.

 

[Sally Mills]

Hi Lee. Thanks for replying.

the fuse thats tripping is a B50A circuit breaker 30mA on my domestic board. The 62A RCD is in the studio next to a B50A circuit breaker neither of these trips.

 

[LeeH]

So it’s possible it’s an earth fault.

You need to get the Insulation resistance measured on the Kiln. Was this done after the elements were replaced?

 

[Spoon]

People. This is a duplicate post. As the other post has more replies I would suggest all future replies should go onto that post, as to stop any confusion.

Problem with 11KW Kiln - https://www.electriciansforums.co.uk/threads/problem-with-11kw-kiln.136200/#post-1355809

 

[Sally Mills]

No insulation resistance measurement taken that I know of but will ask kiln engineer. Many thanks