Temperature Controller Wiring

[BigStoo]

I've wired up both my temperature controllers. The heating circuit works fine, but for some reason as soon as it switches to the cooling circuit my RCD trips.
I've wired them according to this diagram. Apologies for the quality. I'm not using my own computer and I couldn't figure out how to draw straight lines
You get the idea anyway.

The bit in the middle, marked LEN is a simple terminal block.

So, is there any reason my this would trip an RCD? Or should I (as I suspect) start looking at my fridge as the culprit?

 

[jamesb]

The wiring looks fine.

Have you tried the fridge plugged into the mains as normal?

Is it the RCD that's tripping or an MCB?

I've got a TC-10 that does this, and I haven't managed to work out why yet. I'm thinking about putting an anti-surge device inline.

 

[jenki]

Like JamesB says, wiring looks fine, AN RCD basically makes sure that there is a balance between phase and neutral, there is a chance that when the controller switches between heat and cool, it is only switching the live, thus for a very quick time there could be an imbalance, and the RCD does what is should. if you can get hold of an RCD tester you could try a ramp test to see when the RCD trips, it should trip at 30mA, but a lot trip lower than this and tend to be very sensitive.

Do you have more than one RCD on your board? i.e. one upstairs and one down? if so you could try a different circuit?

 

[BigStoo]

Have you tried the fridge plugged into the mains as normal?

I've taken the plug off it, so I'd have to put one back on to check it. It was working fine before I butchered it though...

Is it the RCD that's tripping or an MCB?

Yeah, it's definately the RCD

AN RCD basically makes sure that there is a balance between phase and neutral, there is a chance that when the controller switches between heat and cool, it is only switching the live, thus for a very quick time there could be an imbalance, and the RCD does what is should.

That was how I understood it, and what I suspect is going on.

Do you have more than one RCD on your board? i.e. one upstairs and one down? if so you could try a different circuit?

No, but it is a split load board. Half is RCD protected and half isn't. I've got a dedicated ring main going down to my "brewery" (cellar) so I guess the obvious answer is to move it to the non-RCD protected side.

 

[Aleman]

But it is a split load board. Half is RCD protected and half isn't. I've got a dedicated ring main going down to my "brewery" (cellar) so I guess the obvious answer is to move it to the non-RCD protected side.

Do not do that! Water and electricity is potentially a fatal mix . . . Do you have a socket on the Non RCD Side to test it on first?

I must admit that I only had problems with my TC-10 when I had mis looped the neutral side of the wiring on the Brewery distribution board. . . . Once I put the correct wiring in place everything worked correctly

 

[BigStoo]

Well, it appears my fridge is faulty. I've just put the plug back on, and it trips the RCD straight away.
I guess I must gave caught a cable or something when I moved it as it was working perfectly before.