I was making one spur from a power socket as I have done many times.

I did not switch off the electicity and accidentally shorted with the screwdriver the life and the earth copper terminals. There was a big blast and some melting of the tip of the screwdriver but the circuit breaker in the consumer unit for that circuit went off as supposed to.

When I finished the job and restored power at the circuit breaker, everything in the circuit is working, except for that socket. There is no power there.

I have tested the voltage and there is 3.6V in this socket between life and neutral and about 0 between neutral and earth.

The actual cable looks fine.

What has happened, how can I solve it?

I cannot access the junction boxes. They are behind fixed kitchen furniture that cannot be removed.

Thanks,


Antonio

"asalcedo" wrote in message
...

I was making one spur from a power socket as I have done many times.

I did not switch off the electicity and accidentally shorted with the
screwdriver the life and the earth copper terminals. There was a big
blast and some melting of the tip of the screwdriver but the circuit
breaker in the consumer unit for that circuit went off as supposed to.

When I finished the job and restored power at the circuit breaker,
everything in the circuit is working, except for that socket. There is
no power there.

I have tested the voltage and there is 3.6V in this socket between life
and neutral and about 0 between neutral and earth.

The actual cable looks fine.

What has happened, how can I solve it?

I cannot access the junction boxes. They are behind fixed kitchen
furniture that cannot be removed.

Thanks,


Antonio




--

Perhaps short it with your fingers next time probably wouldn't damage the
socket or wiring then

However if you insist on taking unnecessary risks completely disconnect the
socket and test the incoming cables if there is no current there investigate
further back in the wiring.

best not to ignore the problem as there is no telling what may be happening
further back

or check that your house insurance is up to date and keep your fingers
crossed

Tony

asalcedo wrote:
I was making one spur from a power socket as I have done many times.

I did not switch off the electicity and accidentally shorted with the
screwdriver the life and the earth copper terminals. There was a big
blast and some melting of the tip of the screwdriver but the circuit
breaker in the consumer unit for that circuit went off as supposed to.

When I finished the job and restored power at the circuit breaker,
everything in the circuit is working, except for that socket. There is
no power there.

I have tested the voltage and there is 3.6V in this socket between life
and neutral and about 0 between neutral and earth.

The actual cable looks fine.

What has happened, how can I solve it?

You blew the cable probably. Somewhere hidden. Replace it.


I cannot access the junction boxes. They are behind fixed kitchen
furniture that cannot be removed.


Try a sledge hammer. That will remove most things. The ideal antidote to
Ikea.


Otherwise you will have to route the cable some other way.

Thanks,


Antonio

asalcedo wrote:
I was making one spur from a power socket as I have done many times.

I did not switch off the electicity and accidentally shorted with the
screwdriver the life and the earth copper terminals. There was a big
blast and some melting of the tip of the screwdriver but the circuit
breaker in the consumer unit for that circuit went off as supposed to.

When I finished the job and restored power at the circuit breaker,
everything in the circuit is working, except for that socket. There is
no power there.

I have tested the voltage and there is 3.6V in this socket between life
and neutral and about 0 between neutral and earth.

The actual cable looks fine.

What has happened, how can I solve it?

I cannot access the junction boxes. They are behind fixed kitchen
furniture that cannot be removed.

Thanks,


Antonio


I'd say you've connected the live to the neutral, and you're lucky you
don't have fragments of melted screwdriver in your eyes.


Have you considered professional help?

Andy

"asalcedo" wrote in message
...

I was making one spur from a power socket as I have done many times.

I did not switch off the electicity and accidentally shorted with the
screwdriver the life and the earth copper terminals. There was a big
blast and some melting of the tip of the screwdriver but the circuit
breaker in the consumer unit for that circuit went off as supposed to.

When I finished the job and restored power at the circuit breaker,
everything in the circuit is working, except for that socket. There is
no power there.

I have tested the voltage and there is 3.6V in this socket between life
and neutral and about 0 between neutral and earth.

The actual cable looks fine.

What has happened, how can I solve it?

I cannot access the junction boxes. They are behind fixed kitchen
furniture that cannot be removed.

My mate once did the same whilst adding another double socket in the
kitchen, without turining power off (actually he turned power to the other
house ring rather than kitchen). Remember shorting a ring trips at 32A not
16A !!!

He thoughtfully checked both "sides" of the ring where he had shorted and
one side had no live. I helped him confirm this as well. Disconnect both
the ring L & N at the CU and connect together and resistance check at socket
that they are shorted, one side of ring wasn't in his case. He removed the
kitchen cupboards and cut the cable out from behind the plasterboard and
luckily for him the broken wire was at top of wall where it made a sharp
bend across the ceiling. The live had blown a hole in the cable. The fault
was probably caused by the cable being too tight, he did assure me that he
hadn't pulled the cable down to extend the spur, so might have had the
weakness since kitchen was built.

Anyway cut away section of ceiling added a junction box and new section of
cable made good the repairs and got his mate to properly test the ring to
verify that there were no other issues.

Using the new sockets his toaster worked fine until it burnt the units it
was installed under !!!!

On 27/03/2008 22:50, Ian_m wrote:

Remember shorting a ring trips at 32A

Actually it'll take several times the rated current to "instantly" trip
the MCB, assuming a type B32, between 100A and 150A.

Andy Burns wrote:
On 27/03/2008 22:50, Ian_m wrote:

Remember shorting a ring trips at 32A

Actually it'll take several times the rated current to "instantly" trip
the MCB, assuming a type B32, between 100A and 150A.


And the actual fault current could be 100s or 1000s of Amps!

On Mar 27, 11:41 am, asalcedo wrote:
I was making one spur from a power socket as I have done many times.

I did not switch off the electicity and accidentally shorted with the
screwdriver the life and the earth copper terminals. There was a big
blast and some melting of the tip of the screwdriver but the circuit
breaker in the consumer unit for that circuit went off as supposed to.

When I finished the job and restored power at the circuit breaker,
everything in the circuit is working, except for that socket. There is
no power there.

I have tested the voltage and there is 3.6V in this socket between life
and neutral and about 0 between neutral and earth.

The actual cable looks fine.

What has happened, how can I solve it?

I cannot access the junction boxes. They are behind fixed kitchen
furniture that cannot be removed.

Thanks,

Antonio

--
asalcedo

Alas, I will second the other posters - get professional help and
resign yourself to having to remove the cupboards to get at the fixed
wiring.

A professional will no doubt remove that ring from the CU and perform
quick basic tests to to confirm what people suspect that there is
something seriously amiss with that ring. With the correct test gear
it is possible to check all points on ring and determine the condition
of the wiring - without it you might as well resort to a ouija board
or downing.

Put simply - until that ring passes basic loop tests, insulation tests
and a RCD test you are taking your life in your hands by using it. A
short like that has a tendency to find any weak spot in your circuit
and exploit it.

Even if it seems OK you have no idea if the insualation is badly
damaged enough to cause a fire whilst you are sleeping.

*Only* by using the correct test equipment will you know that.

Unless you are an extremely profficient DIYer and own a multimeter,
insulation tester and RCD tester (and know how to use them) - you
*CANNOT* solve this issue without remaining in doubt that your house
will burn down as you sleep.

Sorry to put a dampner on your evening, but thats my 2 cents.

I really find this derogatory and aggressive tone in many of the replies very sadly typical of many of the posters in this forum.

It turns out that I am an engineer with far too many years of academic and professional experience and who knows about electricity more than just a thing or two. That is why I was willing to take the risk.

I was asking because I did not know what had happened and none of the answer here found it.

Anyway, the problem is fixed. Just a blown 13A fuse hidden behind some kitchen clutter.

A good quality electrical layout that placed fuses for the spurs. I was taking the spur out of this spur, not a ring circuit. And yes, I know the power involved and the diameter of the cable, the voltage and amperage required, and yes, I know that the extra load will never be more than about 10watts and used a 1mm diameter cable for the new spur as a consequence and bla bla bla

asalcedo wrote:

I really find this derogatory and aggressive tone in many of the
replies very sadly typical of many of the posters in this forum.

It might help if you provided the important details that you neglected
to mention in your original post. Your description also did not inspire
confidence since most skilled electricians would not usually take
unnecessary risk of working live when there is no overriding reason to
do so, and when obviously not working with the correct tools and
procedures to do this safely.

It turns out that I am an engineer

You sound surprised ;-)

I was asking because I did not know what had happened and none of the
answer here found it.

Hardly surprising since your description was misleading. It sounded like
you were adding an unfused spur to a ring final circuit. The nature of
the fault you then described would suggest that the ring continuity had
been compromised - hence the concern expressed by some of the responses.

Anyway, the problem is fixed. Just a blown 13A fuse hidden behind some
kitchen clutter.

So you were actually adding another socket to an existing fused spur. In
which case no problem.

A good quality electrical layout that placed fuses for the spurs. I was
taking the spur out of this spur, not a ring circuit. And yes, I know
the power involved and the diameter of the cable, the voltage and
amperage required, and yes, I know that the extra load will never be
more than about 10watts and used a 1mm diameter cable for the new spur
as a consequence and bla bla bla

1mm diameter cable?

Twin and Earth with conductors of at least 1.5mm^2 would have been
appropriate (assuming this is fixed wiring, and not an appliance flex
connected to a FCU that you are talking about).

--
Cheers,

John.

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snip
I really find this derogatory and aggressive tone in many of the
replies very sadly typical of many of the posters in this forum.
/snip

sorry if you feel that way, not trying to be insulting. check my other
posts I am trying to rewire my entire house and have commented on the
same thing.

out of interest, if you were adding a new socket to a fused spur, at
the very least you could of simply removed the fuse the spur if you
could not be bothered to properly isolate.