Shocks off dishwasher

[Matty o]

Had a call
For sometime the owner was getting shocks off the dishwasher if they touched the sink at the same time.

Tested 103v between the 2

Pat tested the dishwasher found live to metal 0.63 ohms traced fault to moulded plugtop replaced plug all tested fine with over 500M

now the problem
I Still have the 103v I tested by hand and there is defiantly a tingle

Tested the ring main at the CU
L-N >500M
N-PE >500M
L-PE starts at 360M but rises to >500M in seconds

Now i realise L-PE is lower but its still well in

The fault is on the ring as the fault is only there when that mcb is live

Before i start taking it apart and check each cable any ideas


Zs0.19
Ze0.54

 

[ayjay]

what was the fault in the plugtop?

 

[telectrix]

have you done IR test and esrth continuity on the dishwasher. that's the first suspect.

 

[dim_bulb]

Is there bonding in place

 

[Brightspark2]

So you have cpc countinuity from plug top to metal casing?...

And cpc at socket, im geussing thats the Zs?...although do you have the Zs and Ze the wrong way round there?...

 

[Matty o]

Did not open the plug top as its a sealed one but with the lead disconnected from the dishwasher i had 0.63M between L-PE fitted new lead and plug top and now have >500M
Dishwasher tests ok now.

Checked bonding is present at CU but cant get to the other end as a new kitchen has been fitted blocking the stopcock but it must be there as the shock is between the sink and dishwasher.

Sorry Typing mistake with the Ze, Zs

for some reason i dont think i tested for continuity from plug top top to casing only insulation resistance and voltage best check that.

Is also a bit odd that the circuit is on a rcd and that tested ok

Think i will go back and test the case continuity and take a wandering lead and check the sockets

 

[YoungBart]

**Views Of an apprentice coming up, So likely to be wrong**

Could it be possible that any metallic pipework into the dishwasher has some sort of voltage to it? causing the problem? If there hasn't been any supplementry bonding in place?

 

[telectrix]

highly unlikely. water feeds to dishwashers are always in plastic hoses.

 

[telectrix]

i suugest plugging a different appliance ( wahing macne , say) i the same socket and checking for that 103V. if it's still there, suspect the circuit. if not, then it's the dishwasher.

 

[snowhead]

Checked bonding is present at CU but cant get to the other end as a new kitchen has been fitted blocking the stopcock but it must be there as the shock is between the sink and dishwasher.

Have you tested between the sink and anything else other than the dishwasher?

Is the dishwasher new?

Are the pipes to the taps plastic?

Is the sink bonded?

Has the dishwasher been left in use?

Access to the stock cock needs sorting by someone as well.

 

[Geordie Spark]

Have you tested between the sink and anything else other than the dishwasher?

Is the dishwasher new?

Are the pipes to the taps plastic?

Is the sink bonded?

Access to the stock cock needs sorting by someone as well.

I agree. How the hell are you supposed to turn the water off if you need to otherwise??

Kitchen fitters ..... Pah!!!

 

[Matty o]

Have you tested between the sink and anything else other than the dishwasher?

Is the dishwasher new?

Are the pipes to the taps plastic?

Is the sink bonded?

Has the dishwasher been left in use?

Access to the stock cock needs sorting by someone as well.

dishwasher around 4 years old but has been like it from new

Not tested with anything else yet

Pipes to tap are copper

no bonding on sink

advised not to use dishwasher and unplugged but they have been using it like it for 4 years so i am sure its back in use now

Agree about stopcock and advised as such

Going back Monday

 

[valleybilly]

New kitchen fitted , no rcd protection , stop tap behind DW hummmmmmm Has DIY B+Q monkey say monkey do written all over it

 

[Matty o]

has rcd but is not tripping but disconnection times tests ok

 

[Guest112]

id aslo recommend plugging in another appliance atleast you can recognise if it's the appliance or the fixed wiring, i suspect it's the appliance leaking to earth and if it's not bonded maybe the rcd isn't picking up the leakage?? but saying that it should trip on the inbalance

hmmm strange fault that one, for curiosity sake please let us know the cause when you find it lol

 

[valleybilly]

earth leakage clamp meter a must on these problems , I must get 1 lol

 

[Matty o]

Been back today but had to leave
so far

Dishwasher Moulded plug faulty, live to earth
Dishwasher metalwork not bonded to earth
Dishwasher live leaking to earth

House live to earth pinched at socket upstairs (the whole 4 bed house and garage sockets are on one mcb)
garage lights wired to house sockets.

Going back Saturday to strip the dishwasher i did tell them to get a new one cant believe they have put up with getting shocks off it for 4 years

 

[44ALLAN]

now the problem
I Still have the 103v I tested by hand and there is defiantly a tingle.


mmmmmmm why do you have a death wish??

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[barneybhoy]

I know this is probably a stupid suggestion but is it possible that the problems with the pipe work and not the dishwasher? Maybe plastic pipe fitted somewhere between sink and main bonding or its not properly bonded. it could be sitting with the fault on the pipes/ metalwork and by touching the sink then the dishwasher it has a path to earth. Have you tried checking between the sink and other appliances? I know it's most likely to be the dishwasher but its worth checking