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- Mar 28, 2008
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Senario:-
done a domestic rewire or CU replacement.
customer now has split load board with RCD fitted.
you explain the new board, identifying MCB's main switch & RCD to customer.
and you want to show them what happens when a genuine earth fault occours, how to reset the RCD.
NOTE:-
RCDs such as MK when fault trip sit in a half-way position not all the way down as when press T button.
You can put your tester on to a circuit, but than can all look a bit to technical for the customer.
RCD deliberate fault inducer:-
13a plug short bit of flex batten lampholder 15w pygmy bulb
wire batten lamp holder accross 'live' & 'earth' at plug
(this will put a earth fault approx 60ma)
Plug lamp into suitable RCD protrected circuit.
Tell customer to watch CU,
Switch on lamp... RCD trips....leave lamp plugged in!
Try reseting RCD customer sees it re trip cause fault still on.
Go along switch off all RCD potected MCB's
Reset RCD,
Go along each MCB in turn until RCD trips again.
Explain to customer this is the faulty circuit and to leave that MCB off whilst re energise all other circuits & RCD.
Tell customer to go round all outlets on faulty circuit unpugging appliances checking for faulty accessories. etc..
Some customers suss this out quite quick when you show it as a proper simulated fault.
for others it can be a good memory jog exercise when they ring you up 4months later because the kettle or steam iron has tripped the RCD!
you are not explaining from scratch over the phone... just remind them
"do you remember when we switched all the curcuits off and rest them one at a time?"
It has helped me quite often to do some quick "remote diagnostics" over the phone.
Other Problems it helps:-
MK type RCDs which trip to mid position and have to be reset manualy fully off before they can be put on.
I have had customer ring up saying they cant reset the RCD its just loose in the middle wont stay up.
As the RCD is much stiffer than an MCB I have had a customer (elderly genteman) say the RCD was jammed and couldn't reset.
When they have seen it trip & reset it a few times they know what they are doing more easily..
Whereas if they have never reset the RCD it can sometimesbe a bit of a stumbling block.
The pygmy bulb is also very good when replacing old non-RCD Cu's
before your take the old board off, show the customer that your bulb (wired to earth) works ok on the old CU. Then after with new CU they can see that appliances or extension leads could be faulty even though they
"worked alright on the old fusebox!"
Also the lamp and plug fit nice in a medium size Jiffy-bag in your toolbox,
ready for use but protected from breaking the bulb!
arghhh me fingers are worn!
my beers all drunk! :_| not time for bed!!
Well
done a domestic rewire or CU replacement.
customer now has split load board with RCD fitted.
you explain the new board, identifying MCB's main switch & RCD to customer.
and you want to show them what happens when a genuine earth fault occours, how to reset the RCD.
NOTE:-
RCDs such as MK when fault trip sit in a half-way position not all the way down as when press T button.
You can put your tester on to a circuit, but than can all look a bit to technical for the customer.
RCD deliberate fault inducer:-
13a plug short bit of flex batten lampholder 15w pygmy bulb
wire batten lamp holder accross 'live' & 'earth' at plug
(this will put a earth fault approx 60ma)
Plug lamp into suitable RCD protrected circuit.
Tell customer to watch CU,
Switch on lamp... RCD trips....leave lamp plugged in!
Try reseting RCD customer sees it re trip cause fault still on.
Go along switch off all RCD potected MCB's
Reset RCD,
Go along each MCB in turn until RCD trips again.
Explain to customer this is the faulty circuit and to leave that MCB off whilst re energise all other circuits & RCD.
Tell customer to go round all outlets on faulty circuit unpugging appliances checking for faulty accessories. etc..
Some customers suss this out quite quick when you show it as a proper simulated fault.
for others it can be a good memory jog exercise when they ring you up 4months later because the kettle or steam iron has tripped the RCD!
you are not explaining from scratch over the phone... just remind them
"do you remember when we switched all the curcuits off and rest them one at a time?"
It has helped me quite often to do some quick "remote diagnostics" over the phone.
Other Problems it helps:-
MK type RCDs which trip to mid position and have to be reset manualy fully off before they can be put on.
I have had customer ring up saying they cant reset the RCD its just loose in the middle wont stay up.
As the RCD is much stiffer than an MCB I have had a customer (elderly genteman) say the RCD was jammed and couldn't reset.
When they have seen it trip & reset it a few times they know what they are doing more easily..
Whereas if they have never reset the RCD it can sometimesbe a bit of a stumbling block.
The pygmy bulb is also very good when replacing old non-RCD Cu's
before your take the old board off, show the customer that your bulb (wired to earth) works ok on the old CU. Then after with new CU they can see that appliances or extension leads could be faulty even though they
"worked alright on the old fusebox!"
Also the lamp and plug fit nice in a medium size Jiffy-bag in your toolbox,
ready for use but protected from breaking the bulb!
arghhh me fingers are worn!
my beers all drunk! :_| not time for bed!!Well
)
