Electrical problem - Fuse getting hot

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Mark274

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We have a fuse that is getting very hot, it is for the shower on it's own circuit.

The fuse blew at christmas but has been ok since.

Our lass noticed a smell the other day and traced it to the fuse box, the brown fuse holder has distorted slightly because of the heat.

Anyone any ideas before I call in a sparky?


Mark
 

Benji

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Sounds like the shower is potentially pulling too much current, is the pump limescaled up, it might be a good plumber you need more than an electrician. I would hope that the shower is on an ECB trip and not just a fuse. But if the fuse is getting warm it is possible the cabling is getting hot too, which is a potential for a house fire, get it checked out and quickly.
 

Dave

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It's a sparky you need and I'd suggest you don't use the shower until it's been checked out

What rating fuse wire have you got in the fuse holder and what Kw rating is the shower?

The fuse holder should not be getting hot at all, sometimes it could appear slightly warm after continuous prolonged use if the shower is using a lot of power especially in the colder months, but if it's getting hot enough to smell it then you've got a definate problem somewhere in that circuit which could lead to a fire

Also, showers these days generally run a minimum of 8kw, often into the 9's and 10's and fuse boxes with fuse holders are not capable of giving the users sufficient protection against electrical shock should a fault arise
You really do need to have the shower circuit protected by an RCD which will detect the slightest electrical leak and shut it down long before a fuse will blow
In addition older showers used to be wired in with 6mm T&E cable which for prolonged use is only really suitable for 7.5-8.0Kw
If your shower is rated higher than this you do need to make sure you have 10mm T&E cable to supply it
 

Mark274

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Cheers

The fuse has been taken out until it is all checked out.

The fuse is 30amp, the shower is 9.5kw.

The original shower was fitted about 20 years ago but was replaced a couple of years ago.

Our lass will have to get on the phone tomorrow and get someone out, anyone know a good sparky in the teesside area?
 

Dave

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On full power your shower will be using approx 39.5amps, (not allowing for diversity - one for the sparks), and not taking into account any resistance on the cable or it's length

If running on full power, so to speak, then this could cause the overheating problem at the fuse.
Get the shower checked out and at the same time it'd be wise to see about getting the cable changed to 10mm T&E plus definately an RCD in the circuit for safety reasons - there's no point being clean if you're fried [;)]
 

ojfrancis

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by the sounds of it, you are using a old style of commsumer unit, which uses fuse wire, if i was you i would pay the money and get it changed, just don't pay more than 500quid for it. the other problem might be that the cabling you are using is not shower cable, this should be changed esipscally if you have had a new shower fitted.
 

Dave

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Oj, the old style fuse boxes are still okay to use as long as they are functioning correctly, and there's very little to go wrong with them

The problems arise when circuits are added or added to or when items such as showers, external floodlights, multi coookers , etc are added or changed as generally the previous wiring circuits aren't up to handling the increase in current required

An RCD is not a legal requirement for a shower circuit but it's most definately wise to have one in place, likewise for sockets that are likely to be used for supplying outside equipment such as garden tools, etc

As for "Don't pay more than 500..."
Changing a consumer unit is like opening up a can of worms as the existing circuits need testing to ensure they're safe and comply with BS7671, likewise earth bondings need checking - most old houses don't have secondary bonding, and that is before the sparky can change the CU afterall once he/she does they are accepting responsibility for that installation and have to certify that it is correct

...so if you're all up to spec and nothing needs changing, fixing or rewiring, expect to pay in the region of 300-400 for a CU change
If everything needs doing then expect up to a full rewire
 

Mark274

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We've got a spare RCD, it used to be for the stair lift so hopefully it will be able to be used for the shower.

The wire is multi core, I took the front off the shower and had a look earlier.

Cheers for the advice Dave, were trying to sort a sparky out to get it sorted asap.
 

simonelsey

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Originally posted by Dave

Oj, the old style fuse boxes are still okay to use as long as they are functioning correctly, and there's very little to go wrong with them

The problems arise when circuits are added or added to or when items such as showers, external floodlights, multi coookers , etc are added or changed as generally the previous wiring circuits aren't up to handling the increase in current required

An RCD is not a legal requirement for a shower circuit but it's most definately wise to have one in place, likewise for sockets that are likely to be used for supplying outside equipment such as garden tools, etc

As for "Don't pay more than 500..."
Changing a consumer unit is like opening up a can of worms as the existing circuits need testing to ensure they're safe and comply with BS7671, likewise earth bondings need checking - most old houses don't have secondary bonding, and that is before the sparky can change the CU afterall once he/she does they are accepting responsibility for that installation and have to certify that it is correct

...so if you're all up to spec and nothing needs changing, fixing or rewiring, expect to pay in the region of 300-400 for a CU change
If everything needs doing then expect up to a full rewire
You can buy mcb modules which replace the old fuse type fitting , just unplug and replace with correct rated mcb .[;)]
 
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Enigma

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At least there was a fuse in the distribution box...I've seen nails being used before and not only were they hot it was throbbing......silly buggers.

Benji and dave have given some good advise here.......clean n crispy is not the way to go.
 

Mark274

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Originally posted by simonelsey

You can buy mcb modules which replace the old fuse type fitting , just unplug and replace with correct rated mcb .[;)]

That's what was recommended and done.

Cheers peeps
 

stevieb

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Originally posted by Mark274

Originally posted by simonelsey

You can buy mcb modules which replace the old fuse type fitting , just unplug and replace with correct rated mcb .[;)]

That's what was recommended and done.

Cheers peeps

Thats all very well but an MCB and a RCD are two different items!!!
A Miniture Circuit Breaker (MCB) is ok to replace the fuse. A Residual Current operated Device (RCD) protects against any current leaking to Earth and must trip the circuit in less than 0.4seconds (in the case of a shower). An RCD should be fitted AS WELL as an MCB. If your cable is only 6.0mm and your Shower is 9.5kw then the cable is NOT capable of carrying the 40amps required. You run the very serious risk of overheating the cable and causing a fire..... Is it worth putting you and your family at risk??? please get the wiring checked by a qualified electrician who knows what they are doing.

Steve
 

ojfrancis

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one of the jobs i was on today, with the 2 other lads was scary, in the CU one fuse had constantly been blowing so some idiot had put a peice of copper wire in instead, then the main fuses blew (60amp fuses/catridge) and the same idoit put copper wire in the 2 fuses
 

Dave

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Mark, I take it you've just changed the fuse for a 40Amp MCB ?
If so you've now got 40amps feeding a shower in a wet environment that may have a fault and anyone using it will be at risk of killing themselves
Trust me they'd be dead before the MCB trips

5amp is enough to give a fit person a good shock
13amp will throw you across a room if you're lucky - heart stopper if not
30amps+ will stop a healthy heart in a split second
80-100amps - you'll get a discount at the cremtorium

Add the presence of water (not only what you're in contact with but airbourne particles, ie steam) and each level is amplified

If you value yours and your family's lifes, get it checked properly by someone who knows what they are doing not someone who's just telling you how to save a few quid
 

simonelsey

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Dave you be suprised at what can kill you .
1mA-2mA barely perceptible , no harmfu effects
5mA-1mA Throw off , painful senstion
10mA-15mA muscular contraction cant let go .
20mA-30mA Impaired breathing
50mA and above ventricular fibrillation and death ,
MCB I only suggested as a another way forward instead of new consumer unit .
As said RCD and MCB are different .Shower should be on RCD as said by someone it checks earth leakage .
 
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chris w

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mark do yourself a favour and listen to good advice mate otherwise the only fishing you will be doing will be at that great big lake through the pearly gates

if you live in a council house or private landlord get them to sort it out pronto if its your own house get the leccy in sharpish.

oh and ive always been told that 1 amp is enough to kill you if you are properley grounded
 
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Benji

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Worse thing you can do it touch something with one hand, with the hand to a good earth point, at this point bang straight across the heart. If you are like me I suffer early in the year with static shocks very badly, including one episode where i was knocked to the floor and with a burnt finger tip, this happened in a cookware shop just trying to pick up a whisk.
 

simonelsey

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Originally posted by Benji

Worse thing you can do it touch something with one hand, with the hand to a good earth point, at this point bang straight across the heart. If you are like me I suffer early in the year with static shocks very badly, including one episode where i was knocked to the floor and with a burnt finger tip, this happened in a cookware shop just trying to pick up a whisk.
I would suggest something in the cookwareshop is leaking electricy to earth you are very lucky indeed.
 

chris w

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Originally posted by Benji

Worse thing you can do it touch something with one hand, with the hand to a good earth point, at this point bang straight across the heart. If you are like me I suffer early in the year with static shocks very badly, including one episode where i was knocked to the floor and with a burnt finger tip, this happened in a cookware shop just trying to pick up a whisk.
have same problem whilst walking around asda and tesco pushing the troley if i touch the metal frame

i get hit with static discharge
 

mickaxon72

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your 9.5kw shower will pull at maximum 39.58amp , if you have 6.00 mm cable protected by a 30amp fuse will easily carry 38amps with out a problem . no real need to go to 10mm ( protected by a 40/45amp fuse.
you will never run the shower long enough to cause a problem. the fuse getting warm is more than likely a lose connection . could be either live or neutral thats lose any were from the incomer to the shower . the shower circuit does not need to be rcd protected it is only a recomendation not a regulation ..
 
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