10.5kw shower wired in 10mm twin n earth on a 40A breaker a problem

[giddash]

Hi there,
I did wired 10.5kw shower with a 10mm cable on a 40A breaker for an old lady's bathroom.she recently got a builder in to do some tiling work and this guy thinks the wiring is wrong and that i should have use 45A breaker else the house will catch fire.I don't think his is right as there no way this could happen as I did test the breaker and it tripped in less than 5s but tought i should post this any way.

 

[somersetsparks]

45A would be better, 10.5 is approx 46A, However it wont trip unless you leave it on all day.

 

[Guest111]

What was the length of run,what was your Zs reading ? what was the rererence wethod,clipped direct for instance and finally are you qualified?

 

[needasparks]

Perhaps you should tell the builder to carry on digging holes as your the qualified installer who has done the calculations ( have you ?)

 

[telectrix]

just wondering how you tested the breaker.

 

[electric will]

How did you test the breaker to make sure it tripped under 5 seconds.

 

[telectrix]

short circuit???

 

[needasparks]

just wondering how you tested the breaker.

Might be a new gadget........

 

[electric will]

And a stop watch, be interesting to see that test. Wonder what the pfc was?

 

[needasparks]

And a stop watch, be interesting to see that test. Wonder what the pfc was?

Stopwatch, cutters and...............Go

 

[electric will]

November the 5th?

 

[DurhamSparky]

another 2 bit DI not having a clue...!

 

[Deleted member 26818]

The only problem I can see, is that the breaker may continually trip.
Why the builder thinks it might cause a fire unless it's replaced with a higher rated device is anyone's guess?

 

[electric will]

The only problem I can see, is that the breaker may continually trip.
Why the builder thinks it might cause a fire unless it's replaced with a higher rated device is anyone's guess?

Tripped in 5 secs? maybe that's where the test result come from

 

[rich.250]

Down rating is renowned for starting fires obviously!!!! Lol

 

[electric will]

I'm still more interested in how the breaker ( assume mcb ) was tested

 

[tony mc]

No mention of RCD ?

 

[needasparks]

No mention of RCD ?

I think thats where the test is getting confused

 

[rich.250]

Obviously has equivalent test equipment to cb manufacturers....
Surely the design calcs should e done before install?? Or am I doing it wrong.... Lol

 

[Deleted member 26818]

It will probably turn out that it's an RCD and it's 40ms not 40A.
Doesn't matter though the ramp test came in under 5s so all's good.