MCB on Wylex board

shoggy · 17 Jun 2006

Hi, I'm wondering if I can put any type of MCB on a standard consumer board. I've got a problem with my low voltage lighting tripping the type b 6 amp MCB when I turn them on (every now and then), so I thought I might swap it for a type C jobbie, but wylex don't seem to do a type C in the plugin type of MCB.

Anyone have any ideas? I also tried to put in a dimmer instead, but it made the lights buzz, even when fully rotated.

Adam_151 · 17 Jun 2006

No Never seen C curve breakers for wylex standard boards, and you can't just swap breakers for C type just like that, you need to check your ELFI is in spec for C type

I recommend trying a 5A BS1361 fuse, and the Z's for the fuse are less 'strict' than for a B6 breaker, but don't let that fool you into thinking it'll make the problem worse, a breaker when enough current flows will usually trip in ~10ms, but if enough current for a fuse to disconnect in 0.4s flows, it'll take around 0.4s (obviously it gets nearer to instant the more current flows though) , so there is more time for the arc in the lamp to extinish, etc

(technically this is notifiable under part P, you are changing circuit charateristics)

plugwash · 17 Jun 2006

btw you can still get rewirable carriers for wylex standard boards

Adam_151 · 17 Jun 2006

plugwash said:
btw you can still get rewirable carriers for wylex standard boards

Yuck!

Given the choice of B curve breakers and cartirdge fuses, I'm not sure why anyone would choose to use a re-wireable fuse

, I can't think of any situation where it would be preferable to both of the other two...

Maybe i'll figure that out when I work out why they still sell wylex standard boards...

shoggy · 17 Jun 2006

by the fuse do you mean one of these?

http://www.tlc-direct.co.uk/Products/WYNSC05.html?

Would that just replace the old 6A MCB?

RF Lighting · 17 Jun 2006

shoggy said:
by the fuse do you mean one of these?

http://www.tlc-direct.co.uk/Products/WYNSC05.html?

Would that just replace the old 6A MCB?

No. That is the right sort of fuse, but the carrier is for the new range of wylex CUs and will not fit the old range.

Spark123 · 17 Jun 2006

I thought you said you had plug in MCBs?
http://www.tlc-direct.co.uk/Manufacturers/Wylex/Wylex_Standard_Carriers/index.html
Or the ones Plugwash was referring to:
http://www.tlc-direct.co.uk/Manufacturers/Wylex/Wylex_Rewireable/index.html
BTW, why the negativity to rewirable fuses Adam?

shoggy · 17 Jun 2006

I was an idiot and couldn't find the right ones on TLC

thanks very much guys for your help, much appreciated

Adam_151 · 17 Jun 2006

Spark123 said:
BTW, why the negativity to rewirable fuses Adam?

They just strike me as rather crude and archaic, and I believe their performance alters slightly depending on how well it was wired, more importantly, open to abuse (wrong wire, multiple wires, paperclips, etc), they don't really have anyway of containing (or suppressing) an arc (though their low Ka rateing reflects that), its possible that if they weren't pushed in properly that melten fuse element could be thrown out anywhere and as these are often found in the back of cluttered cupboards etc...

The only reason we still have them IMHO is while they are poor, they arn't that bad that they should all be ripped out immediatly etc
, but I don't think its a particulaly great idea to be putting them in

RMS · 17 Jun 2006

rewirable fuses.

disadvantages:

1/ easily abused when the wrong size fuse wire is fitted(accidently or intentionally).
2/fusing factor of around 1.8-2
3/precise condition for operation is not easily predicted.
4/do not cope well with high short circuirt currents.
5/fuse wire can deteriorate over time.
6/danger from hot scattering metal if fuse carrier is entered into the base when the circuirt is faulty.

On the other hand they are cheap to buy and maintain(no mechanical moving parts), but would i still use them even now when there is a much more sophisticated means of protection out there.

no way! (edited as i used caps and did not know caps meant shouting)

Pupster01 · 6 Nov 2006

As a tempery addition in a new house ( 1900's build but its new to me)which was rewired in the 1990's , my current intention is to replace the fuse carriers with plug in MCB's ( http://www.tlc-direct.co.uk/Manufacturers/Wylex/Wylex_Standard_Range/index.html ) as i don't have the cash currently for a full Panel upgrade and don't want to be at the wrong end of a wired fuse should i drill through a cable

can anyone see an issue with doing this? or for that matter a reason to change the consumer unit at all once the MCB's are in place? as i quite like the idea of being able to remove the MCB put it in my pocket and know that it can't be switched on while i'm working on a circuit

the house is in Watford, Herts, uk incase anyones got local regulatory knoledge

JohnD · 6 Nov 2006

sorry made a mistake

delmel · 7 Nov 2006

Have you resolved ?.

A quick thing you could do is swap over a matching 6amp mcb from another circuit in the fuseboard. This may seem daft but they all have different tollerance levels.

This may cure it, make sure your not overloading the circuit or mcb.

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MCB on Wylex board

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