Problem with 11KW Kiln

[Sally Mills]

6.5cm diameter. Nothing written on cable but here is a picture

View attachment 40712

Followed cable further down and found 2541M engraved onto cable!

 

[Octopus]

Followed cable further down and found 2541M engraved onto cable!

Keep looking and you may well find the core sizes on their too.

look for 4mm, 6mm, 10mm ....

 

[DPG]

As Murdoch says, the upfront RCBO doesn't seem necessary. Tel's idea of changing it for a fuse may be wise. After the necessary testing obviously.

 

[Sally Mills]

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What does the certificate for the fuse board change state?

Looks like the small CU has a RCD too ........... which one is tripping?

Wonder why the installer fitted an upfront RCBO ?

I asked electrician to replace board as the kiln cable had almost caused a fire inside the old plastic board (melted the casing a little)!! Scary!. He decided to put the RCBO in.

It is the CU (on the left in picture) on house board that trips. The RCD on the right is for the lighting circuit of house.

 

[ruston]

What did he say in his opinion had caused the cable to overheat .

 

[Sally Mills]

Did the spark not fit the SWA cable?

Cable fitted 10 years ago by newly qualified friend!! Always wondered if he did the right thing.

Really appreciate all your advice. Without finding the cause I have no business. Just though many heads better than one as I am desperate and I was right..you're all great. I'll make you all a cyber cuppa
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[Sally Mills]

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What did he say in his opinion had caused the cable to overheat .

He thought the cable wasn't screwed in properly on old board...but it was all melted so not sure how he can tell.

 

[davesparks]

I think the 50A breaker is a bit tight for an 11kw heating load. At 232v that works out to 47.5A.

Only if it’s 11kW at 232V, if it’s 11kW at 240V then it’ll be less at 232V

 

[ruston]

Ok , that happens too .
If the wall that the cable is on is south facing and gets lots of sun , and judging as it is business use and is on for long periods - that cable is going to have a good start at getting preheated.
It could be as has been said before the insulation resistance has been compromised. , or the cable has been damaged by the first overheat incident.
If I were you I would get a reputable electrician to inspect and test this circuit .
Maybe someone on here is nearby.

 

[Andy-1960]

Only if it’s 11kW at 232V, if it’s 11kW at 240V then it’ll be less at 232V

True, but what the betting it’s rated at 230v