Discuss nicely fried - 9.5kw shower, not certificates for the job in the Electrical Forum area at ElectriciansForums.net

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buzzlightyear

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just got back from a customers ,hoping it a nice job and it was ,customers saying I cant push the isolator to the off position .
off comes the isolator wow that isolators fried ,so 6mm cable in and terminals tight has a ducks a88,now for the shower 9.5 kw .
now what about the rcd for it ,nice new bath room , wait a minute a 50amp so where is the rcd for this none .
looking at the 50amp no rcd, no rcbo and mem board and a wylex mcb . customer when was this fitted 3 months ago . so no test certs .
the customers says a bloke who comes to the local pub ,he does elcertics & plumbing came recommended and done a lot of bath rooms
so any test certs, why . if he does not test it then he is non compliant ,with who ,building control .so me and the customer had a chat about it .
 
So what caused the failure ?
6mm cable should handle 9.5Kw
what was the capacity of the switch ?
Or was it just loose connections
No test certs did not cause the failure
neither did rcd's
was it wrong size / type switch ?
What did the customer say to the cost of doing it right ?
we want details !
 
Loose connection on the live, I’d say.
I never use a pull cord for a shower. Always too tight.

Was it an existing shower before the bathroom was done, maybe matey in the pub thought a new switch or new shower was like for like replacement and didn’t need an rcd.

Wylex breaker in MEM board. Now that’s unforgivable!
 
the possible the out going tails was not tight down on the switch isolator, but it saw tight .any way sticking a shower on 6mm boarder,has you say 50 amp no RCD.and a mixed mcb to boot .
 
So what caused the failure ?... we want details !

This is such a common failure in the UK it's got rather boring. It's a combination of barely adequate switch construction resulting in high heat dissipation at the contacts even under good conditions, poorly terminated cables and the stress of forcing the cables back into the box loosening them and displacing the switch contacts. If any contact or termination is not 100% perfect, it will heat enough to oxidise, thermally relax the screw pressure, increase resistance and slide down the slippery slope to this point or worse, by which time it can be hard to point the finger at the switch or the installer.

I think the standard design is daft. The switch should be mounted into the box, then wired in situ, then the cover fitted. That, and a few more pennies spent on the switch spring action and contact design, would prevent most of these.
 
This is such a common failure in the UK it's got rather boring. It's a combination of barely adequate switch construction resulting in high heat dissipation at the contacts even under good conditions, poorly terminated cables and the stress of forcing the cables back into the box loosening them and displacing the switch contacts. If any contact or termination is not 100% perfect, it will heat enough to oxidise, thermally relax the screw pressure, increase resistance and slide down the slippery slope to this point or worse, by which time it can be hard to point the finger at the switch or the installer.

I think the standard design is daft. The switch should be mounted into the box, then wired in situ, then the cover fitted. That, and a few more pennies spent on the switch spring action and contact design, would prevent most of these.
That's what I like about the Crabtree p/switch,50A rated and fixed to the ceiling before cables connected. S
 
I like the Crabtree ones, but generally I don't like pull-switches anyway. I prefer to bring the cable to a back-box on the wall outside the bathroom. Especially with 10mm cable. If you fit a double box like this


you can bring the cable into one side, cross over into the other side where the switch goes, and send it back out to the shower...plenty of room, fit a blanking plate, and you've got a perfect place for a small stash...
but I am going to put my tin hat on now...
 
i had to replace a crabtree the other week. it had gone O/C. then again, i had fitted it in 2004 and the client had been using it as an on/off switch for 15 years, so can't crumble.
 
All down to price, Buzz...
Imagine if you quoted for a job and chose good gear at say £10 more?
No chance!
[automerge]1567355429[/automerge]
10K for a new kitchen?
No problem.
2k for a rewire to keep everything safe for years?
No chance!
 

Reply to nicely fried - 9.5kw shower, not certificates for the job in the Electrical Forum area at ElectriciansForums.net

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