Neutral and Earth wrong way round


C

chrisproud

I'm been slowly checking all the sockets in my new house (1930s). In
one socket I found the neutral wires were in the earth terminal and
the earth in the neutral!!! How could this work? I thought any current
feeding back through earth would trip the circuit beaker. Apart from
further dodgy wiring in the house, could this be an indication of a
bigger problem, ie circuit breaker not working?

I'm going to keep checking and fixing the rest of the sockets in the
house, not being an electrician I can only really check the wires and
the correct way round and secure. Is it worth getting a qualified
electrician in to run some continuity checks etc? What else could they
check for?

Cheers

Chris
 
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I'm been slowly checking all the sockets in my new house (1930s). In
one socket I found the neutral wires were in the earth terminal and
the earth in the neutral!!! How could this work? I thought any current
feeding back through earth would trip the circuit beaker. Apart from
further dodgy wiring in the house, could this be an indication of a
bigger problem, ie circuit breaker not working?
A circuit breaker in a household fuse box only trips if the current is
exceeded. You have to have a RCD type device to trip on earth current which
you probably don't have.
 
M

meow2222

I'm been slowly checking all the sockets in my new house (1930s). In
one socket I found the neutral wires were in the earth terminal and
the earth in the neutral!!! How could this work? I thought any current
feeding back through earth would trip the circuit beaker. Apart from
further dodgy wiring in the house, could this be an indication of a
bigger problem, ie circuit breaker not working?

I'm going to keep checking and fixing the rest of the sockets in the
house, not being an electrician I can only really check the wires and
the correct way round and secure. Is it worth getting a qualified
electrician in to run some continuity checks etc? What else could they
check for?

Cheers

Chris
MCBs are like fuses, they only trip when excess current flows, so
no they don't care about live or earth. It does mean you've got no
working RCD, which probably isnt a problem, but can be in a
minority of cases. Are you in country or town? Do you have
something marked as an RCD or ELCB?

E/N swap is only a tiny risk. It means that like most oldish installs,
things haven't been checked in a while.


NT
 
C

ChrisP

If its an old house new to you and you are only able to check sockets - yes.
Ask for a Periodic Inspection Report.     Was nothing said about the state
of the electrics during the house purchase?  If so definately get the PIR
and revisit your legal advice.  If not put that down to experience and get
the report anyway.

Thanks Jim, nothing was mentioned on the survey when I purchased the
house (I used the banks full survey option, cost me £1500 and they
were rubbish!). Think it will have to go down to experience!

Any idea what I can expect to pay for a PIR in Greater London?
 
M

meow2222

I'm been slowly checking all the sockets in my new house (1930s). In
one socket I found the neutral wires were in the earth terminal and
the earth in the neutral!!! How could this work? I thought any current
feeding back through earth would trip the circuit beaker. Apart from
further dodgy wiring in the house, could this be an indication of a
bigger problem, ie circuit breaker not working?

I'm going to keep checking and fixing the rest of the sockets in the
house, not being an electrician I can only really check the wires and
the correct way round and secure. Is it worth getting a qualified
electrician in to run some continuity checks etc? What else could they
check for?

Cheers

Chris
MCBs trip on overcurrent, so they won't care. It means you have
no working RCD or ELCB supplying the sockets, which is usually
not a problem, but if you're out in the country on a TT install that
would be a big problem.

The risk caused by a N/E swap is tiny. It means your electrics havent
been checked in a while, which is usual for non-new installs.


NT
 
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A

ARWadworth

David Hansen said:
On Sun, 16 Mar 2008 03:31:38 -0700 (PDT) someone who may be


There are several types of circuit breaker. They work in different
ways to detect certain types of fault. Without more information on
what sort of circuit breaker you are talking about it is impossible
to say whether it should have detected that particular fault.
Also a RCD will not trip with a NE reversal at a socket unless that socket
is used.

Adam
 
J

John Rumm

Peter Parry wrote:

I would agree with most points, but:
nor does it need to), that it needs a new consumer unit (it probably
doesn't) and a rewire (it almost certainly doesn't). It will also
Much depends on the state of the cables. A '30s place could well still
have rubber insulated wiring and urgently need rewiring.
 
M

meow2222

Peter said:
On Sun, 16 Mar 2008 16:26:59 +0000, John Rumm


It could, but as it already has MCB's that is very unlikely. Even if
it was rubber it might well not even be picked up in a Periodic
Inspection Report unless its somewhere it can be seen without lifting
boards etc. PIRs are far more of a customer paid for sales
opportunity for electricians than anything useful.
I'm wondering how practical it is to suggest the OP could do the
main points with a bit of reading or explaining. Its not particularly
hard.


NT
 
C

ChrisP

The house has been rewired, I'm just not sure when.

The offending socket has been used fine, including a vaccum cleaner
which i think consume a fair number of watts.

I've checked a few more sockets and found loose wires where spurs
(sometimes more than one!) have been added. Just looks like a bad DIY
by the previous owners I can rectify myself.

Thanks everyone, your comments are very helpful.
 
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E

Ed Sirett

I'm been slowly checking all the sockets in my new house (1930s). In one
socket I found the neutral wires were in the earth terminal and the
earth in the neutral!!! How could this work? I thought any current
feeding back through earth would trip the circuit beaker. Apart from
further dodgy wiring in the house, could this be an indication of a
bigger problem, ie circuit breaker not working?

I'm going to keep checking and fixing the rest of the sockets in the
house, not being an electrician I can only really check the wires and
the correct way round and secure. Is it worth getting a qualified
electrician in to run some continuity checks etc? What else could they
check for?

Cheers

Chris
As others have said this will not cause a circuit breaker to trip.
Given that this particula fault is rather rare (it is plausible to
misplace Line and Neutral bit much less the Earth with a Conductor).
It brings a serious question mark over the whole installation.
 
A

Andy Wade

Andy said:
I don't see the relevance of the age.
If the cabling is pre-1984 2.5 mm^2 T&E - quite possible in view of the
older BS 3871 type MCB mentioned - then the earth conductors acting as
neutral will only be 1 mm^2 and could be liable to serious overheating
under overload, not protected by the MCB. With later 2.5 T&E the
problem won't be quite so bad.
 
J

John Rumm

ChrisP said:
The house has been rewired, I'm just not sure when.
Thinks like a whole house RCD would date it to somewhere early 80's
(like the place we just moved into)
The offending socket has been used fine, including a vaccum cleaner
which i think consume a fair number of watts.
With a TN-S or TN-C-S earth, then it probably would work ok... not good
though!
I've checked a few more sockets and found loose wires where spurs
(sometimes more than one!) have been added. Just looks like a bad DIY
by the previous owners I can rectify myself.
Loose wires are not uncommon on older installs. It would probably be
worth the tedium of taking off every faceplate and tightening as
required and carrying out a visual inspection as you go.
 
M

meow2222

Andy said:
(e-mail address removed) wrote:

I don't see the relevance of the age. Neutral-Earth swap is just wrong,
whenever it was installed.

Or do you have in mind the interesting image you've given me - that if
you don't keep an eye on them, the wires will move about? :p

Andy
lol


NT
 
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D

DanS

nothing was mentioned on the survey when I purchased the
house (I used the banks full survey option, cost me £1500 and they
were rubbish!). Think it will have to go down to experience!
If you just had a survey - even a full one - a surveyor will carry it
out. They are looking at the structure of the building and the result
usually explicitly says that it is not an electrical survey.

I gave up having electrical surveys after just one as it seemed to be
more concerned with the fact that the house did not fully meet the
_current_ wiring regulations and had some 45 degree cable runs and did
not spot the spur from spur from spur set up in one room. I was more
worried that there might be something dangerous in place.

dan
 
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