Electrickery sort of question

[HasBean]

I'm getting a bit miffed about having to reset the house consumer unit mcb when I use my mig. On full wack it sometimes trips the 25A breaker in the consumer unit (used to be 20A but got changed somehow ) but never trips the type C 16A mcb it feeds off in the garage. It's a radial circuit about 15-20m long on 4mm T&E, feeds a double socket supplying two bedside clocks, drops down into the garage where I've added a small consumer unit to seperate power to lights/sockets etc and then back upstairs to the bathroom heater. All these items are fused (having once lost a substantial amount off a screwdriver after having been told all 3 phase power had been cut I tend to be a bit belt and braces these days )
I have 'obtained' a 30A mcb for the Wylex (house) CU. Would I be pushing my luck fitting this to hopefully stop the startup tripping bearing in mind everything is fused to the hilt?

Ideally a seperate supply off a sub board would be the answer but at the moment It's not justifiable (and digging up the front room might upset the missus, strange girl)

Paul

 

[chriskelland]

Hi Paul,

Most consumer units are fitted with 'B' type mcb's, you say you have a 'c' type in the garage and does not trip. You should be able to change the 'b' type in the consumer unit for the same current, but 'c' curve. I have the same problem. After flooding the 'Lecky' fitted a new consumer unit, now keeps tripping out when I start my Rage up, used to have a buzz box which did the same thing, the new inverter seems OK.
Just cant seem to find a 'c' curve 20 amp mcb to fit a LeGrande consumer unit.

Chris.

 

[madkayaker]

Chris try www.rswww.co.uk for the breaker. Paul follow Chris's advice that should fix the problem

 

[chriskelland]

Hi M K,

Not trying to hijack the thread, but are most of the consumer unit mcb's all din rail? I know what I need but can't find a legrand supplier. I've looked in RS but would another make fit? p.s. tried going back to my 'Lecky' but did not have a clue what I was talking about, hope the job he did is OK!

 

[madkayaker]

All circuit breakers are din mounted but the pin location is different. Take a breaker out and go to a local wholesalers and find one that has the terminal in thew same place. The outgoing side doesn't matter as cable bends! (unless its been overloaded then it snaps) If memory serves wylex is the same as legrand but can't be sure.

 

[madkayaker]

Chris
http://www.thefusecompany.com/fuse.php?products_id=787
Hope this helps

 

[HasBean]

I've been in contact with Wylex and they don't make a type C breaker for my CU unfortunately

 

[madkayaker]

Crabtree make one and its the same as wylex. How old is the CU it could be an old design that clamps under the screw instead of the clamp system. Take the cover off and photograph the bus bar if your not sure.

 

[HasBean]

It's about 20yrs old, the breakers do clamp under the screw (it's the old Wylex NN I think).

 

[madkayaker]

Oh knackered breaker for that are like rocking horse droppings. Wyles have started using that system again I don't know if the new will fit in the old.

 

[chriskelland]

Hi,

Thanks for the link to the Fuse Company, MK. I ordered a 'D' curve breaker and next day had a message left on my phone to call them. I spoke to a great guy called Brian, who wanted to make sure I knew what I had ordered. How many firms would do that? Anyway it came next day and is now installed and I have been trying to get it to trip with no success, so job's a goodun! BTW I have 16 amp Wylex b curve breakers in the workshop and none of them have ever tripped, so I checked them and seem OK.

HasBean, I can suggest that you ring the Fuse Company and speak to Brian, I'm sure he will be able to help. 0151 933 1143.

 

[HasBean]

Thanks mate I'll give them a ring