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Topic Title: WYLEX MCB replacements
Topic Summary: MCB tripping
Created On: 12 October 2007 12:28 PM
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 12 October 2007 12:28 PM
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wendyb

Posts: 11
Joined: 12 October 2007

Hi !
Complete novice here... so bear with me!

I have just had a 9.8KW shower & 10mm cable installed. The electrician said a 40 AMP MCB would 'probably be ok so long as you don't run it on full power'.
I now find I can't use the shower without it tripping out. is it possible to buy a 45 or 50 AMP MCB for the following:
WYLEX
80AMP
240Vac 50HZ
BS5486 Pt:13
Cat no NNES 914

I hope this is the info needed. I wrote down pretty much any info i could find. The MCB's have Type 1 & Type 2 written on them. the electrician said it was an old one.

If I can't get one - what's the alternative???
Any advice hugely appreciated!
 12 October 2007 12:55 PM
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Avatar for OMS.
OMS

Posts: 19661
Joined: 23 March 2004

Well,

Notwithstanding an abnormally long cable to the shower - a 9.8kW model should be hovering around the 41Amp mark - so in theory, if you are not in the habit of taking showers of about 4 hour duration this should't be a problem.

I would suggest that a competent electrician examines the whole installation - including taking a few measurements of actual current flow before taking the "easy" option of simply upping the MCB rating

Perhaps those with a more direct link to equipment availability will comment on the specific breaker swap

Regards

OMS

-------------------------
Failure is always an option
 12 October 2007 01:00 PM
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perspicacious

Posts: 7232
Joined: 18 April 2006

Welcome Wendy

Long term, you ought to be concerned as to what certification you received from your "electrician" and whether your Local Authority Building Control are aware of this work being carried out, as from what you have described as his working practice, it is unlikely.

Regards

BOD
 12 October 2007 01:29 PM
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wendyb

Posts: 11
Joined: 12 October 2007

Hi OMS,
Thanks for your advice. It's very helpful & much appreciated. The funny thing is the shower worked yesterday evening ( albeit only for a few mins when we just wanted to try its temperature ) - but the fuse tripped out when we went to use it this am.

I will use your advice and aks for it to be re-tested.

Thank you!
 12 October 2007 01:33 PM
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Avatar for OMS.
OMS

Posts: 19661
Joined: 23 March 2004

........... and as BoD pointed out - get proper certification for it from the electrician - if you havn't got it already - don't pay him cos the job aint finished till the paperworks done (Excuse the somewhat lavatorial humour in that comment)

Regards

OMS

-------------------------
Failure is always an option
 12 October 2007 01:35 PM
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wendyb

Posts: 11
Joined: 12 October 2007

Hi Bob,
A registered company did the installation. We are waiting for the installation certificate, which we were told would be issued and sent in the post.
My worry was that we might not be able to get the MCB in a higher AMP becuase apparantly it's an old one- but OMS says this may not be the problem ( or solution).

Thank you for your advice.
 12 October 2007 01:50 PM
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wendyb

Posts: 11
Joined: 12 October 2007

oops.... we have paid them already.... ! I thought the certificate was sent from somewhere else? Hope fully I'm correct and all will be well....

Your advice is very much appreciated.
thank you.
 12 October 2007 02:14 PM
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OMS

Posts: 19661
Joined: 23 March 2004

Well it may be sent from the electricians office (if thats what you mean by somewhere else - but I suspect not)

I'm assuming this electrician both supplied and installed the shower along with the upgraded cable so he should have provided an electrical installation certificate.

You mentioned registered - if the certs don't turn up soon - contact whichever body he is registered with giving as much information as possible.

You may or may not be aware that this work was also notifiable to your local building control body asit falls under Part P of the Building Regulations. Either yourself or the electrician (if part of a self certifying scheme) had an obligation to notify.

Regards

OMS

-------------------------
Failure is always an option
 12 October 2007 02:18 PM
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deejackson

Posts: 266
Joined: 13 May 2005

There are two pieces of paperwork involved here. The first should be a Minor works certificate or an Electrical Installation certificate (depending on the extent of the work). This should be completed by the installing electrician (detailing circuit characteristics and test results)and one copy presented to you. The second piece of paper is a building control certificate - this may take some time to come through. Building control will either have been notified prior to work commencing, or, if your electrician is part of one of the part P schemes then notification should have occured at completion.

Hope that helps

Dee
 12 October 2007 02:34 PM
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perspicacious

Posts: 7232
Joined: 18 April 2006

"A registered company did the installation"

Whilst not exhaustive/up to minute, the link below may be your first step to finding out the company's status regarding Part P and lead you to the scheme they are with.

Regards

BOD



http://www.competentperson.co.uk/search.asp
 12 October 2007 02:38 PM
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iie62478

Posts: 220
Joined: 14 October 2005

Wendy,

Does the mcb trip immediatley the shower is turned on or only after a period of time. if the former then it sounds like you have a fault on either the wiring or the shower.

Terry.

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Are we all in this together???
 12 October 2007 02:41 PM
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perspicacious

Posts: 7232
Joined: 18 April 2006

As OMS posted, I would want to know why the 40 A circuit breaker is tripping, as even 50 A (ie approximately 12 kW)on a 40 A circuit breaker for an hour is extremely unlikely to trip it.
Putting a 45 A or 50 A one with their associated higher tripping currents may only mask what appears to be an under lying problem that could be a fire risk.

Regards

BOD
 12 October 2007 03:02 PM
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Avatar for potential.
potential

Posts: 1264
Joined: 01 February 2007

Let's hope the 40A MCB just controls the shower!
Anything else go off when it trips?
I wouldn't fit a load of 40+ amps onto an old 80A box anyway, too much of a strain.
Is the MCB getting hot or anything else, main switch or cables?
 12 October 2007 03:33 PM
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wendyb

Posts: 11
Joined: 12 October 2007

Thank you for this advice. I was not aware that we had to register it under building regultions. We have been in contact with the electrician who said the work should have been done at the office. He said he would chase it up. I will follow up all of your advice
Very many thanks for your help and advice.
 12 October 2007 03:36 PM
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wendyb

Posts: 11
Joined: 12 October 2007

Hi BOD
Many thanks I will look this up .
 12 October 2007 03:44 PM
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wendyb

Posts: 11
Joined: 12 October 2007

Hi Terry,
When we tried it yesterday it ran ok ( admittedly this was for a few minutes only)- although it didn't seem very warm on the medium setting. When we went to use it this am the fuse went almost immediately - it tripped out each time we re-set it .
I don't know if this is relevant but we were told when the guy installed it that we must be careful to switch off the shower switch each time as "this type of shower will burn out if you don't".( It's a MYRA Sport 9.8KW) I was surprised abut this & the guy added "Yeah- I managed to burn out a shower I had like that until i realised".
No idea of this is significant or just a point of fact . I am still surprised though!
 12 October 2007 04:06 PM
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Veglen

Posts: 99
Joined: 07 June 2007

Wendy,

I hate to play devils advocate here but have you expressed your concerns to the electrician that installed the cable and shower, and is he aware of the problem you are experiencing?

If so, what has his response been so far?

Also, wasn't the question of a larger MCB asked when the electrician suggested that "40AMP MCB would (probably) be ok, so long as you (don't run it on full power)."

Just trying to understand what kind of guy this electrician is!

V
 12 October 2007 04:17 PM
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wendyb

Posts: 11
Joined: 12 October 2007

Hi V,
My inital enquiry was about locating a 50 AMP MCB for the circuit board. The electrician said a 45 AMP was not made for that type of circuit board . We thought we might be ok with a 40 AMP but after it tripped out we decided to see if we could get hold of a 50 AMP from somewhere - this was after the electrician said we might need to fit one bigger instead. He said he couldn't get hold of one . ( It is an old circuit board)- which is why I contacted the forum.
I have been in contact with the electrician who is going to come & have a look at it.
 12 October 2007 05:22 PM
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Veglen

Posts: 99
Joined: 07 June 2007

Thanks Wendy

Obviously the shower and circuit requires re-checking and further tests carried out.

However, from your description the shower alone, all be it not for long periods, could take 50% of the total power handling capacity of your consumer unit. Also, 30mA protection to the shower should be considered for extra safety.

Personally, I would advise you to have a new consumer unit (quite expensive). An alternative would be to split the load from the meter and use a separate one or two way consumer unit (less expensive) this could then be used to protect the shower and have a possible spare! I would also advise that the main in coming supply fuse is upgraded if less than 100A

The electrician should be able to advise you further, if you have any confidence in him that is! However, if not, I'm sure the members on this forum will help you and give sound advice!

Good luck

V
 12 October 2007 06:22 PM
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sparkingchip

Posts: 6031
Joined: 18 January 2003

May be it's a bit late now however, if I had supplied and fitted the Shower and it would be a problem replacing the breaker I would have got a 8.5Kw Shower or if you the Customer was getting the Shower I would have told you to do the same.

So if the Electricians supplied the Shower it's up to them to sort it out, if you bought it then you are going to have to have a discussion as it was not matched to the available breaker, so you were master of your own destiny, bearing in mind the Electrician should have know better as the expert and carried out the correct installation, charging as required for sourcing a correct breaker or even changing the consumer unit.

sorry, Andy.
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