Shower replaced by plumber blows fuse

[loz2754]

Got called to customer who has had a shower replaced 2 months ago by a plumber. Keeps blowing the fuse...

Turns out the replacement shower is rated at 10.5 kW.

Here is a picture of the consumer unit:

The shower is actually fed from the 15 amp BS1361 fuse for the immersion heater, next to the lights. Along with the immersion heater!
The fuse carrier is now permanently welded closed.

The good news the circuit is wired in 10mm cable.

Bloody plumbers!

Needless to say I'll be returning next week to test the whole flat and replace the consumer unit...

 

[westward10]

The lights on the 32A breaker?

 

[loz2754]

Well spotted

 

[buzzlightyear]

Whoho, a lighting on a 32 amp.i was first. Lol.

 

[loz2754]

Incidentally I've decided to go with 2 side by side consumer units instead of a dual tariff. Tons cheaper.

 

[Timbo]

What's an "IMMERS HATER"?
On peak 3.

 

[Pete999]

What's an "IMMERS HATER"?
On peak 3.

Heater that don't like getting wet?

 

[Vortigern]

Snap! just last week doing EICR found 9.5kw shower on 32a MCB and 6mm² and the terminations were tight, so tight I could not undo the L cable screw, welded.

 

[nicebutdim]

In laws got a shower upgraded to 9.5kW, a couple of years back, and recently asked me to take a look a it as fuse was blowing periodically.

You guessed it - 32A fuse in a melted carrier and 6mm cable.

Told them to get a spark in as a matter of urgency and not to use that shower until then. It's going to be a new board for a number of reasons, so it seemed best that the news should come from someone with qualifications. Chances are they've ignored the advice and will carry on until they break the fuse carrier. Terminations are all good and show no signs of thermal damage, but that fuse must be getting seriously hot.

Apparently the spark who installed this shower mentioned that the set up "wasn't ideal".

 

[Mike Johnson]

I am very old fashioned and have always fitted gravity showers in my properties, do people go for electric showers because they are easier to fit, or is there some other reason?

Or on another tack, with the modern trend towards mains pressure hot water tanks, I would think shower installations will change in the near future.

 

[pc1966]

I am very old fashioned and have always fitted gravity showers in my properties, do people go for electric showers because they are easier to fit, or is there some other reason?

Endless hot water without a combi boiler?

At least until the electric bill comes along!

 

[Mike Johnson]

I suppose it does away with the HWT and unfortunately the airing cupboard, does that mean that people without airing cupboards all have linenfold cupboards instead ? or am I just showing my age.

 

[pc1966]

Airing cupboards were handy places for wine/beer brewing.

 

[Mike Johnson]

And starting off your veg.

 

[littlespark]

I think I’m going to beat you, but I’ll have to get back into the customers house to take a photo for proof.

32A mcb to 4mm t&e.
t&e into 13A switch fused outlet
2x 1.5 t&e then to shower.
Couldn’t see rating plate on shower, but guess 7kW or above

I will be tearing this out in the coming weeks, and it’s already disconnected, by me... as the customer said the shower doesn’t work, and they’re remodelling the bathroom.

I suppose, if they had the shower on low, the 13A fuse might have held???

 

[James]

I think I’m going to beat you, but I’ll have to get back into the customers house to take a photo for proof.

32A mcb to 4mm t&e.
t&e into 13A switch fused outlet
2x 1.5 t&e then to shower.
Couldn’t see rating plate on shower, but guess 7kW or above

I will be tearing this out in the coming weeks, and it’s already disconnected, by me... as the customer said the shower doesn’t work, and they’re remodelling the bathroom.

I suppose, if they had the shower on low, the 13A fuse might have held???

I would look at the "fuse" with great suspicion

Even if it looks like a fuse, I have a funny feeling that inside it will contain no fuse wire but possibly a screw or other large conductive material.

 

[James]

also, remember that the rating of 2 x 1.5mm twin + E in parallel is more than 32A in free air.
Unconventional but apart from the 13A FCU it might even comply for a 7kw shower.

 

[marcuswareham]

I am very old fashioned and have always fitted gravity showers in my properties, do people go for electric showers because they are easier to fit, or is there some other reason?

Or on another tack, with the modern trend towards mains pressure hot water tanks, I would think shower installations will change in the near future.

I have fitted an electric shower in my house,

no gas only electric, problem is hot water tank is only big enough for 1 bath or shower, and cannot get a bigger tank in due to space restrictions, so as soon as the other half has had a bath no more hot water ,and i heat the tank over night on eco 7 so dont really want to heat it in the day for a shower, I know the electic shower is using peak rate electic but only for the shortish time i use it and it is always ready to go

Likewise a friend of mine lives in a flat with a gravity feed system (tank directly above the cylinder so very low pressure due to being able to lift the shower head above the head of water) he tried fitting a shower pump, had to cut an essex flange in the side for air free connection as couldn't get surry flange on top of cylinder as it is to close to header tank, if the shower pump is connected to the cylinder top pipe / vent pipe it pulls air in

because of the essex flange the shower will never use top 1/4 of the tank and then compounded by the small tank size it means bearly enough hot water for a shower unless your very very quick

Not everyone lives in a house with space and central heating ?, so electric showers deffinatly have there uses, alot of people dont like them, I find them absolutely fine if you buy a decent power one (and keep the shower head and hose which it came with)

Alot of people prefer Combi boilers now due to instant hot water and only heating what you use, so same benefits to electic shower if you dont have gas,

 

[brianmoooore]

Your friend's set up looks like a classic case for upgrading to a mains pressure cylinder. This could be much bigger than the existing cylinder, since it can use the space occupied by the storage tank as well, and can feed a decent shower directly.
In your case, where you have limited hot water capacity, heated by off peak electricity, an electric shower makes perfect sense, but ultimately, the best electric shower is a poor substitute for any decent shower fed by a hot water storage tanks.
Combi fed showers are better than electric ones, but still a long way short of a storage fed one.

 

[marcuswareham]

Your friend's set up looks like a classic case for upgrading to a mains pressure cylinder. This could be much bigger than the existing cylinder, since it can use the space occupied by the storage tank as well, and can feed a decent shower directly.
In your case, where you have limited hot water capacity, heated by off peak electricity, an electric shower makes perfect sense, but ultimately, the best electric shower is a poor substitute for any decent shower fed by a hot water storage tanks.
Combi fed showers are better than electric ones, but still a long way short of a storage fed one.

Yes in his case mains pressure cylinder probably would be the best option