Mixed MCB's callout

[GreekIslandLover]

Went to a callout in a disabled care home last night. No lights, and power missing to one floor. Also the door closures didn't work. It's a rambling old Edwardian place sprawling over several floors. Under the circumstances, there wasn't an option to say they had power to most of it - we'll come along Monday to have a better look. It had to be resolved. Spent a while running up and down five floors to find the various DB's. The place had been added to over the years ant it was a bit of a spiders web. Found the incoming board and the board on floor 4 (it HAD to be one of the upper ones didn't it!). Worked out no power coming into floor 4 DB, so went back to basement to take a closer look at the main DB.

The upshot of all this is that when one of the light bulbs went ping taking out all of the lights, the care worker flipped the breaker on again. They also noticed that some of the other mcb's were off and flipped them on too. At that point they found out they couldn't open the doors or have power on floor 4. What had happened at some point on the past was that someone had jammed in Legrand MCB's in another manufacturers board. These breakers were on in the opposite position from he rest, so when the care worker flipped the ones that were off back on, they were in fact cutting off the power to other places.

Moral of the story - fit the right kit when altering stuff!

 

[green-hornet]

I bet you was relieved when you found out what it was

 

[Nicky Tesla]

yes ive seen that on some old vertical board somewhere, only they where the correct mcbs but some had been fit the wrong way round.

 

[GreekIslandLover]

I bet you was relieved when you found out what it was

Oh yes! Having a rambling huge building you've never been to and finding your way round it, plus careworkers giving you lots of third hadn info and not knowing where anything is, plus the residents wanting to chat, plus knowing youlve several more calls ahead doesn't make for an easy call. No pressure.

Went back to basics and ignored all the info from the punter. Tested supply into board 4, took front of main board and tested supply coming out of all breakers. Noted that the ones with no output were the Legrands and flipped them the other way to see what happened. Sort of lucky find really. I guess if I'd have started taking the punters information too seriously I'd have never got there.

 

[Evans Electric]

A good point to remind Forumites that some older MCBs switch the other way, I think Dorman Smith is one. They were all standardised at some point.

You need to watch out also for the red or green colour indicator on old MCBs and also industrial switchfuses ( MEM, BILL etc) Today red means ON (danger) green means OFF (safe) On the old ones it was the other way round.

Deke