Burning smell from shower

[NickGee]

Hi

Bit of an worrying experience this evening.

Son is having a shower, everything as normal. Then the bathroom is full of a pungent burning smell - no smoke, and the smoke alarms fitted upstairs didn't make a peep.

I switch everything off, and isolate all the different bits and pieces, and sniff out the problem.

The smell was coming from our Triton T80 10.5kw shower. I take the back off, and sure enough locate the culprit.

The input lead which has brown and blue cables goes into a connector box (I think that's what it's called) which holds the cables in place with screws. The other side of this box splits off to the various parts within the shower.

The blue (neutral!) input side cable is scorched, as is the input connector side. The plastic looks slightly melted and the screw is clearly burned.

Oddly, perhaps, none of the fuses, the trip switch for the shower, or the master RCD kicked off.

I'm thinking leave it isolated and alone and get a professional out. But what sort of damage is likely to have been done? Is it going to be fatal to the shower, or is it a minor fault which is more obvious coz of the large currents flowing. Perhaps of greatest concern, why didn't any trip? Usually a lightbulb blowing can trip the RCD!

Any thoughts or suggestions welcome!

In anticipation!


Nick

 

[Lectrician]

A loose connection can quickly cause terminations to overheat.

Most likely will require new terminal blocks and the supply cable re-terminating. It may require some new internal wiring of the shower if this cabling is damaged.

If this fault had escalated to a stage where fire or serious danger was imminent, the protective devices would have operated.

 

[bernardgreen]

If this fault had escalated to a stage where fire or serious danger was imminent, the protective devices would have operated.

The MCB ( or fuse ) will not trip as the loose connection will not increase the current. Only when the joint and/or cable fails to the extent that a live to neutral short ocurs will the current increase enough to trip the MCB. The RCD ( if fitted ) will not trip until a live to earth or neutral to earth short occurs

Until one of the trips operates the loose joint can be heated by the almost the full rated power of the shower.

One reason why terminals should be routinely checked for tightness.

 

[NickGee]

Thanks for the replies folks.

Doesn't sound like too big a job then, which is nice.

Guess I should whip the cover off and check and tighten the connectors every six months or so in future!

Many thanks

 

[Lectrician]

If this fault had escalated to a stage where fire or serious danger was imminent, the protective devices would have operated.

The MCB ( or fuse ) will not trip as the loose connection will not increase the current. Only when the joint and/or cable fails to the extent that a live to neutral short ocurs will the current increase enough to trip the MCB. The RCD ( if fitted ) will not trip until a live to earth or neutral to earth short occurs

Until one of the trips operates the loose joint can be heated by the almost the full rated power of the shower.

One reason why terminals should be routinely checked for tightness.

Thats what I mean.

I said "By the time it gets to a dangerous stage......". The insulation would have melted to a degree where a short between live and neutral OR earth would have occured, operating either the MCB or the RCD. The circuit protection operating as it should.

As all kit we install is to a BS (or so it should be) and we comply with the regs, all the kit is designed to contain the early stages of fire until such time as the devices operate.

 

[Lectrician]

del

 

[Lily7]

A loose connection can quickly cause terminations to overheat.

Most likely will require new terminal blocks and the supply cable re-terminating. It may require some new internal wiring of the shower if this cabling is damaged.

If this fault had escalated to a stage where fire or serious danger was imminent, the protective devices would have operated.

I was here looking for a answer to the same situation, same concern and same model of shower. Your answer was very straightforward and made perfect sense. Especially to me, someone with no electrical expertise. I only just about change the light bulbs Thank you so much