Rcd Spur Went Bang

[sparkyrj]

Hi, I replaced a 13 a RCD spur today as customer had overloaded it and melted in the fuse holder. It supplies a garage that they use for doing art work and they had 2 heaters on it and a kettle now and then and wondered why the fuse was blowing. I bought a new one at QVS as it was nearby, admittedly a cheap ish one. I put the supply back on after fitting it and pressed the reset and all good. However, after resetting after pressing the test button there was a large bang and some smoke. There were no shorts, all connections good and no load switched on in the garage. The fuse in the spur did not blow , nor did the one in the consumer unit. I can only suspect a faulty unit. Has anyone else had this problem.

Thanks in advance.

 

[ProDave]

With SOME makes of RCD (and rcbo) it is VITAL you connect the input and output the right way.  Check your wiring VERY carefully. I suspect you had the input feed connected to the load terminals.  That may not functionally matter for a normal FCU (though it's still wrong) but could be fatal for some RCD's.

However with your description of the loads connected, some more serious re design is needed as with the overloading it's only a matter of time before a replacement fails due to overload. 

 

[sparkyrj]

Thanks for the reply, but it was wired correctly. The supply and load terminals were clearly marked. The replacement is purely temporary to get the lighting working. They have promised not to use the heaters or kettle in there again. I will be requiring the supply from the cons unit shortly as its now just a spur from the kitchen ring.

 

[ProDave]

But did you measure the supply was going in to the supply terminals? or did you just re connect the new one as the old one was wired? it could have been wired wrong originally and would still function.

Otherwise it was a faulty unit.

 

[sparkyrj]

Yes, I had to put a tester on the supply to check when I had killed the circuit. Also , the supply was t+e and the load an armoured

 

[OnOff]

A, erm........."mate" of mine once replaced, wire for wire  a TP RCD that went L1, L2, L3, N with one that went N, L1, L2, L3.........."he" said it was late and getting a bit dark. There was a bang......... :coat

 

[Zeespark]

The load cable was an SWA? odd :innocent

Andy Guinness

 

[Steve3948]

Was it BG by any chance

 

[sparkyrj]

The load goes out to the garage, that's why it is SWA I can't remember the brand Steve, it's out in the van, but it is a cheap one. It's only meant to be a temporary fix.

 

[SLIPSHOD & SLAPDASH]

About 2 years ago a local wholesaler was stocking HAROK  kit. It was identical to Contactum and a quarter of the price. We had about 5 RCBO's go bang on us big time, you could see the scorch mark out the seam in the back of the breaker. They stopped selling them that month as  quite a few people had the same experience. I was shocked to see CEF stocking them and  made them aware of the problems.

 

[sparkyrj]

I've replaced it with a better one, all working ok. Just need to get them to have the job done properly now.

 

[batty]

I did have a TD line RCBO go up in smoke once have fitted a lot since and it was a one of.

 

[Bruspark]

I guess the fuse holder failing before the fuse did on the first is not a sign of quality accessories . . .  

And the new cheapo unit sounds like the main suspect in the second case . .

Quick checks and tests yes but surely try a decent one before wasting too much time there

 

[sparkyrj]

It's fine with a better RCD spur now. I only pressed the reset button after trying the test button and it went bang. I didn't flinch , but the people in the house jumped a bit.

 

[Bruspark]

Sparkrj.   Good work,

We must always maintain our composure while innocently looking round for the source of the curious new burning smell  . . . .