Water heater wiring?

[Mark]

UK

I've got hot water tank that has an economy 7 (night time) heater. But it
keeps burning the insulation on the live (blue) wire. When I rewire it'll
work fine before the insulation burns again and disconnects the wire.

Have I faulty wiring or a faulty heater?

 

[Harry Bloomfield]

Mark wrote on Monday (23/02/2004) :

I've got hot water tank that has an economy 7 (night time) heater. But it
keeps burning the insulation on the live (blue) wire. When I rewire it'll
work fine before the insulation burns again and disconnects the wire.

Have I faulty wiring or a faulty heater?

It sounds most likely to be a poor and high resistance connection, the
connection to which the blue is connected. Blue is (or should be)
nuetral not live BTW.

 

[Fads]

If you look his original post started with UK.

Fads

 

[Harry Bloomfield]

Depends on which side of the Atlantic you are on.

Economy 7 indicates UK

 

[Harry Bloomfield]

Neutral is blue over there, hot (single phase) is brown. I believe 3
phase hots are brown, black & grey.

On flexible cables....

Blue = Nuetral
Brown = Live
Green/yellow = Earth or ground

On non-flexible cable...

Black = Nuetral
Red = Live (single phase)
On three phase.. Red, Yellow, Blue

 

[Mark]

Sorry about the blue (live) confusion folks, I meant to type neutral but in
my haste to fix the problem I typed it and didn't check afterwards.

The wiring and the element has been fine for 15 years.

I've just reconnected it again and will check in a few days to what it's
like. It never blows the fuse.

 

[Mark]

Sorry about the blue (live) confusion folks, I meant to type neutral but in
my haste to fix the problem I typed it and didn't check afterwards.

 

[pablito]

Sorry about the blue (live) confusion folks, I meant to type neutral but in
my haste to fix the problem I typed it and didn't check afterwards.

The wiring and the element has been fine for 15 years.

I've just reconnected it again and will check in a few days to what it's
like. It never blows the fuse.

******************************************
Good Morning Mark,

You may have a short between the heater element
and Ground on the neutral side, which may be providing a
ground path for some other device on your overall wiring
layout, or, possibly the heater is not grounded, and
there is return to ground path for something else back
through the water heater circuit.

I have seen this in the past when the ground on the main
panel was bad, but the ground through the water pipes
was good, and all the neutral currents went through the
path of least resistance back to ground, the hot water
heater wiring.

Sneak ground paths, and overloaded neutrals are hard
to find, and a very common problem, especially on older wiring systems.

Check this with an Ohmeter, ( with the heater element
disconnected, ) read between the neutral side, ( Blue )
wire and Ground. If you find a short, ( unless the Neutral
is grounded deliberatly at this point ) This is your problem.
But you have another problem that you are not seeing,
and that the Neutral return to ground either at your
main sevice panel, or at your meter is open.
This must be a very small hot water heater, as all
heaters I am used to are 240vac, not 120vac..

Have a great day .

 

[daestrom]

Economy 7 indicates UK

Perhaps, but the capital 'UK' on the first line certainly does

daestrom