Wylex Type B BS 3871 Push-in type

[Paul41]

I have installed a 9.5kw triton sport shower. The MCB is a 45A Wylex type B push in type BS 3871 the cabling is 10mm2. The shower has two settings,on setting 1 the shower functions correctly, when switched to setting 2 the MCB trips (obviously when the setting 2 is selected the shower draws full current and trips the MCB is this because it is operating close to the 45A MCB setting) Is there an MCB (60A) replacement which can be fitted in place of my 45A wylex MCB or can I fit a separate unit with RCD protection. Also I got my 45A push in type MCB off ebay because wylex told me that this type of mcb is now obsolete

Thanks for your replies, I have checked current being drawn (clamp meter) and it is 37.5Amps therefore the MCB is not working correctly. Have now decided to fit new consumer unit with RCD protection (sparks already booked to complete work for me)

 

[Steve]

I have installed a 9.5kw triton sport shower. The MCB is a 45A Wylex type B push in type BS 3871 the cabling is 10mm2. The shower has two settings,on setting 1 the shower functions correctly, when switched to setting 2 the MCB trips (obviously when the setting 2 is selected the shower draws full current and trips the MCB is this because it is operating close to the 45A MCB setting) Is there an MCB (60A) replacement which can be fitted in place of my 45A wylex MCB or can I fit a separate unit with RCD protection. Also I got my 45A push in type MCB off ebay because wylex told me that this type of mcb is now obsolete

no!!!! do NOT, i repeat DO NOT up that MCB.

MCBs can run for hours at slight overcurrents. There is something wrong with the shower. At full power your shower should draw 41.3A, at which that MCB should NEVER TRIP. At 46A, the MCB might last for days. Seriously. Get the shower looked at by someone. Is it still under warranty?

 

[Adam_151]

It could be that the CU is not meant to take a protective device over 32A, and heat is being produced where an incompatable device is making bad contact with the CU terminals, and these heat is being conducted into the MCB and tripping the thermal overload part

or it could just be that the MCB is knackered

Recommend you have a separate shower CU installed with RCD and 45A mcb, as crafty points out, 45A is the correct size MCB for that shower

 

[andy]

sounds like a faulty shower to trip the MCB immediatly. get it checked out. i doubt its due to heat thru bad contact as adam says, but its a possibility.

whatever you do, NEVER replace an MCB/fuse with a higher rating unless your 100% sure it can take the extra load

 

[JohnD]

On a slightly different tack, if you bought your MCB second hand on fleabay, who knows what condition it is in. You can still get new 45A MCBs for Wylex, the new ones still fit, but they have a flick switch (up and down) rather than the push buttons of the 1980s version. You can get them for about £7 new, some price variation depending on supplier.

BTW some of the older Wylex standard CUs have a mainswitch rated at 65Amp. The bigger, later ones (metalclad) seem to be 100A and the small 2 or 4 way I think are 45A.

If you have an old small one the main switch might be worn out by now as well as undersized. I notice old ones do not have such a smart snap action. I hope you haven't got one of the brown ones made of mahogany and bakelite, with no plastic shrouds on the incoming terminals?

 

[securespark]

You can still get new 45A MCBs for Wylex, the new ones still fit, but they have a flick switch (up and down) rather than the push buttons of the 1980s version. You can get them for about £7 new, some price variation depending on supplier.

No. The largest modern Wylex plug-in MCB you can get is a B40.

You can get a 45A BS1361 fuse and carrier, though.

BTW some of the older Wylex standard CUs have a mainswitch rated at 65Amp. The bigger, later ones (metalclad) seem to be 100A and the small 2 or 4 way I think are 45A.
If you have an old small one the main switch might be worn out by now as well as undersized. I notice old ones do not have such a smart snap action.

If the board is Wylex Standard range, then any board which has a main switch rating of <100A is not intended to have any device connected to it which is >32A. The lugs on the rear of the fuse shields are intended to prevent this, but most just get snapped off.

The best way to gauge whether a Wylex board has a 100A main switch is to look for markings confirming this. If there are no markings rating it at 100A, then it is safe to assume it is not suitable for any circuit larger than 32A.

BTW, your shower problem could be due to an element problem if there are two elements. When one is on, there is no problem, but when the other kicks in, it trips out.

 

[nmarir]

This is annoying ....Wickes are selling these showers knowing full well that Wylex don't make plug in MCBs at 45A.

They try and sell you one of theirs.....but the pins are too big.

Answer - stick to 8.5kW as these don't need more than the 40A which are available!

 

[GaryMo]

The funny thing is that a shower circuit doesn't require overload protection but do manufacturers instructions actually insist on overload protection?
It's been a while since I've read any MI for showers.

 

[Spark123]

What has Wylex not producing a 45A plug in MCB got to do with Wickes?
Wylex do make a 45A HBC fuse.
The OP is over 2 years old!!

 

[GaryMo]

The OP is over 2 years old!!

I hadn't even noticed that!

 

[breezer]

nmarir, welcome to the forums, i dont suppose Paul41 really cares, since he asked the question over 2 years ago and if that wasnt bad enough, he only ever made the one post

please check the date a post was made before you reply. also read the forum rules.