What's next to my board?

[man2964]

Evening all, I'm relatively new to the trade and have just moved house. Looking to rewire and was looking at a few things, could someone tell me what on earth is next to my board? From what I can see is it looks like two contactors? But what are they likely to do?

 

[brianmoooore]

Is that an interlock device between the two? If so, my guess is that it's a priority device which prevents two heavy loads, such as two electric showers, from being used at the same time and overloading the supply.

 

[James]

It is a pair of mechanically interlocked contactors.

My educated guess would be that it is a changeover switch, possibly automatic.
The clue is the appliance inlet shown at the bottom left of the picture for plugging in a generator.

 

[man2964]

Thanks! Makes sense and I think the guy who originally built it was a builder and into cars so perhaps welding etc?

It looks as if they come straight from the Henley block so how would they trip if they're not through an MCB?

 

[James]

They don’t trip, contactors are basically big relays.

 

[man2964]

They don’t trip, contactors are basically big relays.

Apologies, I mean if somethings plugged in , what protection does it have other than say a fuse if they're fed direct from an Henley block prior to going into any board?

 

[James]

The device on the wall is a plug, not a socket.

The contactors should be wired so that either power is fed from Henley blocks to your distribution board
Or
Power is fed from a generator via the blue plug below to the distribution board.

Power should NEVER be able to flow from grid to generator or generator to grid this would be dangerous for you or anyone working on the grid.

 

[brianmoooore]

My educated guess would be that it is a changeover switch, possibly automatic.
The clue is the appliance inlet shown at the bottom left of the picture for plugging in a generator.

Very likely! Didn't spot the inlet when I first looked at the pic.

 

[man2964]

Ah HA! Thanks guys, I was looking at it thinking what on earth is going on and that if that commando socket were live the pins are very very easily accessible! The advice is much appreciated!!

 

[westward10]

Don't assume it isn't going to be live.

 

[brianmoooore]

There's something odd about that appliance inlet. Doesn't seem to have a base. Looks more like the type that should be attached to a flex.