What's This then?

[acvc]

Can anyone tell me what this is?

I am supposing it's some kind of electromagnetic switch controlled by a timer to control Economy 7 storage heaters. I'm told it's not working and that it's about 25 years old.

Is there anything about today to replace it?

The pic has been sent to me from friend down in Devon who isn't a spark, but tells me it's not working. I haven't actually been there! And besides, I've got no experience with the Economy 7 set-up.

Thanks chaps and chapesses.

 

[acvc]

Heer's another!

 

[acvc]

And another.

 

[Guest123]

Hi.

Looks like a normal contactor to me, you can just make out the A and A1 terminals in the photo.

Theres lots of different types of contactors around today and I mean lots.

Contactors are used to switch large loads by small devices i.e photocells, timers PIR's, to energise heaters, large lighting loads etcetc.

Try a good wholesaler they're bound to have them in stock, just make sure you select the right one for the load and the correct overload.

 

[acvc]

Can I ask a bit more then?

1. This is effectively a clock operated isolator. What wires/cable would be coming on from the clock? I'm thinking small csa here. Would It be a three-core (L, N, E and Switched L)?

2. Installed between e7 c/u and heaters, then: for three installed heaters, I'd need to get an isolatorwith three or more 'ways'/in-outs inside?

4. The three heaters are 2x2.5kW and 1x1.5kW, which means a load of just under 28A. So I'd get a minimum rated 30A contactor with three ways inside?

Thanks again.

 

[Spudnik]

The time clock will bring the contactor in at a certain time to heat up the NSH.

Not even sure they are really needed nowadays.

 

[Guest123]

Hi.

Basically the way it will work is something like a 6A supply from an MCB in a board to the time clock, from here then on the load side of the timeclock a SL + N to terminals A + A1 of the coil in the contactor.

You can either get a double pole contactor and run the supply tails of the heater CU through it or get a larger one and run each individual hetaer circuit through it.

From the photos it seems like a straight swap as it's controlling the supply tails, I would just replace with a contactor rated at the same or larger than the suppliers fuse with a smaller overload to protect the other side.

 

[acvc]

Lenny that's good info, thanks very much.

The larger situation is this:

House in the country, presumably TT.

It's a split phase installation. One phase is going to one end of the building, from which the e7 is fed, as well as lighting and power. I think the tails for the e7 are split at the main switch for the c/u (right side of contactor), and then run to this contactor. (As you say). I've not been there yet.

My buddy down in Devon (non spark) has put a voltmeter across the load side of the contactor and got nothing, so between us we're assuming the contactor has packed in. He's also spotted signs of arcing and burning smell from the enclosure.

I'm probably going to have to go there to replace this. I've never bought or wired a contactor before, and would like to get a replacement up here in Bristol before I go to the middle of nowhere on a Sunday!. Any brands/types you would recommend?

So to sum up: the path is this:

1. timer/clock fed from own way in c/u
2. SL+N from clock to A and A1 in contactor (which way round?).
3. Mains tails split in or before c/u, going into contactor, then out to e7 c/u.

Lastly: get a double-pole contactor rated at the same or more than the supplier's main fuse (e.g. 60/80/100A).

Muchos gracias.