father_jack

Got a dishwasher left behind in our new house, but it gives you an electric shock if you touch the casing while earthed, e.g touching the sink and the dishwasher inner casing.
I've put an earth wire from the casing to the earth point on the plumbing under the sink.
Is it safe to leave it like this or should I chuck it out?

Cheers

FJ

Crypt

It's shocking you because there is a lack of an earth somewhere. .[Prolly the earth wire in the plug come out]
As for attaching it to your sink, that would depend weather all your bonding is on [does it stop shocking you]. If it is then that would be ok, but i'd look at the lead and plug first.

matt.bowey

If the case is live, then there is an internal fault to ground!

Find it, fix it or chuck it out before its TOO LATE!

albob

FJ,
as Crypt says, its usually earth wire out of plug, or
lack of earth in wall socket (shock comes from suppressor/capacitor in machine). If its neither of these its dangerous, and wants repairing (most common fault is heater) or binning !!
alan

David_Wallis

Like Crypt says... could be lack of bonding... dont jump to conclusions that its your dishwasher...(hope it is though) get and electrician around to make sure all your earth bonding is correct...

Got to love PME Installations, till a plumber sticks a bit of plastic pipe in the middle and doesnt bother to bond it before cutting it

Saw a right example the other week when rewiring a mates house.... Wish I had a camera...

Not to mention my sisters new house... Shower in the ringmain... theres some lazy ******* out there...

alcazar

iTrader: (2)

Speaking of showers, I had to refuse to do my mate's shower unless he bought a proper "trip" for it.
We ended up with a brand new fuse box, trips, RCD, £80 all in from Screwfix.

ustolemyname??stevieturbo

iTrader: (1)

So whats the crack with bonding, when virtually all the plumbers pipes are plastic?? Mainly sinks. If there are plastic pipes going to a sink be it bathroom or kitchen, but at ground level he then changes to copper going to the sink. Do you need a seperate earth to ever f**kin sink or rad??? as they arent linked anymore with copper.

David_Wallis

stevie,

I thought you were an electrician by trade, Im not!

As far as I knew you bond every pipe as close as possible to where they enter the building, on the customer side of the meter etc..

Then I thought it was something like additional (sp) bonding in the bathroom if there was electrical things in there... Cant remember exactly as I dont have IEE Handbook Handy.

What I found was Stopcock... 1 foot of plastic pipe and then the bonding.. and i touched them both.. ouch.

David

father_jack

Cheers guys - the plug is moulded on so probably not a loose earth wire in the plug - was getting sparks off the earth lead when I was connecting it has fixed the problem tho, butI think I'll just bin it.

chiark

If there's current there, isn't it evidence of a fault somewhere in the system? If you're protected by RCD, a leak like this would trip the system straight out wouldn't it?

David_Wallis

not everybody has rcd's.

David

Crypt

I doubt he'd have a RCD, besides these only trip with N/E faults and woulsnt trip if there is no earth connected.

Bonding requirements are as follows...

10ml from mains to gas meter and water stop tap.
4ml under sinks (hot and cold) conected to sink top in kitchen.
In the bathroom you now have extra problems with the new regs.
Under the bathroom sink, radiator, light, shower and fan all have to be bonded together! The new amendments to the 16th are going overboard imo.

[Edited by Crypt - 9/30/2002 12:38:56 PM]

father_jack

So does this mean I'm going to die in a dishwashing related incident or not?
Not sure I could stand the shame of that

Crypt

Best thing you could do is get a spark out to check the ring main where the dishwasher plugs in (this can be done in minutes with a meter). Maybe the ring has no earth in which case it's dangerous.

The dishwasher may well be fine, have you checked the lead and where it joins the dishwasher? Do you get shocks off anything else thats pluged in?

I'd be tempted to get someone out to check your ring (sockets). Should only charge you a call out to put a test on it.

David_Wallis

And if your near leeds ill plug a tester in for free..

actually no I wont... need to finish my car

Crypt...

Do you have any link or a copy of the new stuff for bathrooms that you could forward to me?

David

father_jack

Thanks guys - I'm in Edinburgh so I think I'll "get a man in"

Gonna need a DIY forum on here soon .... so sad.

Crypt

David, you can download the ammendments here. IEE

It will be somewhere in there.

chiark

Sorry, I'm being slow here, but surely if the dishwasher is shocking, then there's a fault in it? Earthing it will just shift the problem?

Imagine your dealing with someone really stupid, it is about right in my case

David_Wallis

erm... you can get a shock between earths due to potential difference... In PME installations (Protective multiple earthing) all earths (or all things available) are bonded together along with the neutral... usually as close as they come into the building so you can get a shock between say the sink and erm a dishwasher..

This is why you use rcd's for outside.. incase you find another earth... even though IEE regs say that any supply that could feasably be used outside should be protected by an rcd...

(I know what I mean... but might not make much sense...)

Crypt would be better to explain as it is his line of work!

David

[Edited by David_Wallis - 9/30/2002 3:41:23 PM]

chiark

No, that makes perfect sense - cheers!

logiclee

Just one thing to add.

Get it sorted quickly. It only takes just over 30 milli amps of current flowing through your body to stop your heart.

Most people survive electric shocks due to a dry body having a natural resistance of around 1000 ohms and you are usually insulated from earth by your shoes etc.

Lets assume you have a hard fault on the dishwasher and the dishwasher is not earthed. You are touching the metal sink or taps which are earthed so you yourself are in direct contact with earth. When you touch the dishwasher current will flow through the dishwasher casing through you to earth.
The most likely outcome is that you WILL DIE!!!!

Its not worth DIY ing or messing about with, get someone in who knows what they are doing.

Lee

David_Wallis

And that changes alarmingly when your wet..

Theres a nice chart in the handbook.... eitherway it fooking hurts.

David

mj

to all the sparks / engineers that have replied here.

has anyone got a copy of the 16th edition on CD-ROM that I can "borrow", I HATE trawling through that silly book.

Cheers,

mike.

CrisPDuk

I'm currently thinking about piping two showers in in my house in plastic, how do I earth that?

Crypt

You dont have to apart from the shower itself and the switch. There is no way the pipes can become live if they are plastic.

Mj, sorry I dont have it on CD I too have the books.

However it is avalible on the link I provided on the previous page, though it will probably be silly priced knowing the NICEIC.

ustolemyname??stevieturbo

iTrader: (1)

The regs do go overboard, and I will admit, I havent read them in ages, as they waffle. Im sure they dont take into account howver that working practices are changing. More and more plastic pipe is being used by plumbers, which will affect things. Strictly speaking water should not conduct electricity, but it does. therefore I suppose there may be a requirement for earthing taps etc which are fed from plastic pipes. The regs are unclear though. They may cover some things in bathrooms or swimming pools, but not specifics. They just say earth everything, that way they are covered.
If you are getting shocks, something is wrong, get it checked out.