Don't use Contactum 2 pole RCBO's for Solar PV

[ProDave]

A quick heads up to anyone. Don't use Contactum 2 pole RCBO's for Solar PV

This came from another thread of mine where I needed a mini CU for a shower but there was only a tiny space, so we came up with just a 2 pole RCBO in a slim 2 module enclosure.

I chose a Contactum 2 pole RCBO, and fed the power into the bottom (no manufacturers instructions to say which should be the feed) and the thing self destructed in a puff of smoke on the first press of the test button.

So you CAN'T feed power in to the bottom of a Contactum 2 pole RCBO.

So IF you were thinking of doing anything similar to make a compact mini CU to connect a Solar PV system, you MUST ensure your chosen RCBO can accept power input to either end.

Had you used a Contactum RCBO, even with the supply in the correct end, in the event of the RCD tripping while the solar PV was generating, the "run on" time of the inverter before it shuts down, feeding into the RCBO's output terminals, would likely destroy the Contactum RCBO.

 

[NozSpark]

It's the same for Proteus,,,

But then again they're a last resort anyway

 

[kerching]

I dislike Proteus BUT I also dislike Centaur, so what is it to be FIGHHHHHHHHHHHHHHHHHHHHT...nah just don't buy from CEF...simples............ :coat

 

[batty]

The old contactum RCBO's could be used either way I used them on 16th edition split boards so Kitchen ring could be separate to the other socket circuits. I don't use Contactum boards these days as they haven't got the space for RCBO's.

 

[SLIPSHOD & SLAPDASH]

I can see if feeding the wrong end the unit may not work, but i cant see how it can damage it ?

 

[ProDave]

I can see if feeding the wrong end the unit may not work, but i cant see how it can damage it ?

My guess, and it's only a guess is this.

The "control and detection" circuit is powered from the output terminals.

When it senses an imballance of >30mA it energises the trip coil.

the circuit is latching, so it energises the trip coil until power goes off.

But because power is fed into the "output" side, the power is not disconnected from the detection circuit.

And the trip coil is only rated for brief momentary operation.

So it's the trip coil buzzing, and after a couple of seconds burns out with a puff of smoke.

All just a guess on my part, but I can't think of any other reason why it went pop.

 

[steptoe]

that would make sense

 

[batty]

Dave not saying you are wrong but I had a TD line single pole RCBO that went the same way put it in the board switched it on pressed the test button there was a lot of buzzing then smoke and a bang it was just a faulty item. Contactum, MK and TD line have all got the same casing so possibly are made in the same factory in China.

 

[SLIPSHOD & SLAPDASH]

My guess, and it's only a guess is this.The "control and detection" circuit is powered from the output terminals.

When it senses an imballance of >30mA it energises the trip coil.

the circuit is latching, so it energises the trip coil until power goes off.

But because power is fed into the "output" side, the power is not disconnected from the detection circuit.

And the trip coil is only rated for brief momentary operation.

So it's the trip coil buzzing, and after a couple of seconds burns out with a puff of smoke.

All just a guess on my part, but I can't think of any other reason why it went pop.

Good guess, sound quite plausible, but we have had faulty units and i have connected up 2 pole rcd's the wrong way and they simply did not work. About 1 1/2 years ago we had a load of Harok Rcbo's blow up on being energised. The wholesaler stopped stocking them, but i have seen them in CEF now

 

[batty]

Nice CEF probably took the faulty stock probably saw it as a challenge to get rid of them. I probably shouldn't say that.

 

[steptoe]

:slap

probably not

but possibly correct,

do you think the different branches are running a book on the biggest mark-up?

:slap

 

[batty]

I possibly could not comment but will say they do seem to sell some dodgy gear. I used to subcontract to a firm and a lot of the gear they used was from cities I hated using it it just seemed poor quality and differcult to use.