new shower mcb

[mrcrow]

i have just had the bathroom redone and a new miras shower which is 9Kw
the mcb in the board is 40A

about 2 weeks after the installation the shower mcb would cut out...shower was on max setting... after about 2 minutes

miras engineer had a look at the shower and found no faults...he suggested the mcb might be too sensitive...???

what can i do to ensure the shower will run on max all the time...around 4-6 minutes...my wife likes it hot!

its ok on medium

cheers and happy new year
from manchester

 

[THRIPSTER]

Have you got anything else running from this MCB? (EG: heated towell radiator)

 

[mrcrow]

Have you got anything else running from this MCB? (EG: heated towell radiator)

no nothing like that..we checked all the circuits which were on and they are on separate mcb's
the towel rail is on the ch water...good call though...

i did forget to mention the isolator for the shower was mooted by the miras engineer as a possible place for investigation...i will drop it down..its on a pull cord...and check the contacts for any burning and make sure the terminals are tight screwed...i may replace it with a on off wall mounted switch if i thought it was suspect...

my hidden question here is...for 9Kw which must be nominal and variable...is 40A mcb with its own tolerances...the right one for the duty
would a 50A be ok and still be safe

 

[THRIPSTER]

What size cable is being used?

 

[Spark123]

40A MCB is correct for a 9kw shower. Suggest you get an electrician with a clamp on ammeter to see what current the shower is taking, tho I'd have hoped the service engineer would have done something like this.

 

[mrcrow]

40A MCB is correct for a 9kw shower. Suggest you get an electrician with a clamp on ammeter to see what current the shower is taking, tho I'd have hoped the service engineer would have done something like this.

thanks..if i had of known this i could have had him check...really i didnt interfere with his inspection so i dont know what he did...i should have..

as for the previous poster..thripster...the cable is the one which the last shower used...sorry i cant be more clear at this stage..

i did renew the isolator and can say it was larger cable than the ring main ones...stiff and difficult to get the cables into the box...the next one up i would guess...30A?
its pvc t/e but the cores are braided to let you see the 'age' of the wiring..

when i get a better chance i will strip out the isolator again and measure the cable ...

as for a load reading i will have to get an electrician in to do that soon..

meanwhile we are using the shower on mid settings

 

[Taylortwocities]

A loose connection will not cause the MCB to trip (unless its shorting out).
Are you sure the thing that is tripping is an MCB --or is it an RCD or RCBO. What is written on it?

Only over current will cause an MCB to trip. As suggested above, someone needs to check what the actual max load is.

Also, the size of the cable is not relavent to the tripping issue. (It would be good to check it though!). FYI, most T&E cables over 4mm² have stranded, not solid, conductors.

You must not change the MCB to 50A without someone checking that the cable can support this load otherwise your wife will certainly get hot - just before the fire brigade arrives

 

[mrcrow]

A loose connection will not cause the MCB to trip (unless its shorting out).
Are you sure the thing that is tripping is an MCB --or is it an RCD or RCBO. What is written on it?

Only over current will cause an MCB to trip. As suggested above, someone needs to check what the actual max load is.

Also, the size of the cable is not relavent to the tripping issue. (It would be good to check it though!). FYI, most T&E cables over 4mm² have stranded, not solid, conductors.

You must not change the MCB to 50A without someone checking that the cable can support this load otherwise your wife will certainly get hot - just before the fire brigade arrives

this is on the 'mcb'>....its in the panel and marked shower..others are marked..lights, circuit 1, circuit 2 etc....there is a large one which i think is the earth leakage breaker...and at the other end the on off switch for power..

here are the details<

ching nb1/63
b40 6000
3 230/400
iec/en60898-1
971287

we have been running the shower at mid setting for over 1/2 hour...wife kids etc...and its ok

ps how can i identify the cable rating..it runs in the loft up from the hall then a couple of metres down to the shower..so its not in brickwork
so hopefully it will have some writing on it to be able to check the area

cheers

 

[Adam_151]

A loose connection will not cause the MCB to trip (unless its shorting out).

Except if its the connection to the top of the MCB thats loose, then eventually heat builds up anough to travel back into the MCB and trip the thermal part

 

[Spark123]

ching nb1/63
b40 6000
3 230/400
iec/en60898-1
971287

Do you mean Chint?

 

[Taylortwocities]

= Those low quality products that all qualified electricians install in the quickest possible time....?

 

[mrcrow]

= Those low quality products that all qualified electricians install in the quickest possible time....?

would you suggest a better make in 40A

i can get one locally from an electrical outlet...which make is good

 

[RF Lighting]

Do you still get a free fire extinguisher with every chint CU purchased?

 

[mrcrow]

ching nb1/63
b40 6000
3 230/400
iec/en60898-1
971287

Do you mean Chint?

yes you could be right...chint...

 

[mrcrow]

Do you still get a free fire extinguisher with every chint CU purchased?

ok i get the joke...and need a shower...

http://www.qvsdirect.com/MCB-Type-B-Single-Pole-40A-pr-19028.html

they do a 45A as well...

but no fire extinguisher just a 10% discount at lidl's

edit...they do look cheap

http://www.jkcontrolsystems.com/?gclid=CK-J2syv3ZACFQ3UlAodUlWarA