MCB Removal (Daft Question)

[Charles Middleton]

Due to my problems with LV lighting I've got a Type-C MCB which I need to fit into my consumer unit.

So I turned off the main switch, unscrewed the cover and pulled it off dislodging a number of dead spiders (not pleasant). I the unscrewed the original MCB but amount of pulling or pushing in any direction would release the thing. So I screwed it back in and replaced the cover.

Would somebody mind giving a me a quick overview on how to replace an MOB? Please make as noddy as possible.

Also looking at the front panel of the unit - does the RCD protect all of the circuits or just some of them? The unit is a Hager by the way.

Thanks,

CM

[Andrew Mawson]

They usually clip onto a length of 'DIN' rail screwed to the back of the unit, and to get them off you release a clip (usually at the bottom of the mcb) with a small screwdriver. If you look at your replacement part the clip mechanism should be obvious. Having said all that I've never used a Hager unit so they may be totally different !!!!!

Andrew

btw what's wrong with dead spiders? It's the live ones with big teeth that you have to worry about

[Christian McArdle]

Assuming it is a standard DIN rail, there are two methods (after DP isolating the entire house supply and unscrewing the terminals to the MCB).

1. Remove the entire live busbar and remove the MCB.
2. Find the little sliding clip on the back of the MCB and slide it right out using a small flatblade screwdriver. The MCB should now be leverable out at an angle without having to remove the entire busbar. You may be able to find MCBs without this feature, although I doubt they are common, except in very early DIN rail designs.

I can't tell without looking at it. There are a number of different configurations. However, as a general rule (with attendant exceptions), if there is a separate main switch with a separate RCD, then only some of the circuits are RCD protected. This is a good thing.

Christian.

[John Rumm]

Last Hager one I saw did have spring clips on the MCBs.

[Lurch]

With Hager it's just a case of unscrewing the connections then releasing the clip on the bottom of the MCB. It'll just slide out now. I know this because I fit loads of Hager! ..

SJW A.C.S. Ltd.

[John Southern]

Cheap shit arnt they ? We use Hager 4 way boards in small feeder pilliars for streetlighting.

Jon.

[Lurch]

I like 'em! They're not bad for the money, I've fitted a lot worse in the past. ..

SJW A.C.S. Ltd.