I have a water pump remote from the house which is controlled via an
underground cable and works perfectly.
I am now adding a power socket adjacent to the pump which will allow me to
carry out various operations in the vicinity.
The underground cable has 4 wires and I have arranged for the socket to use
the spare wire as the live connection while using the common earth and
When I checked the socket with my socket tester it showed a neutral fault.
However when I used a circuit tester the light was illuminated.
I have checked the neutral connection and it appears sound.
What can be causing this and how can I correct it?
Without wanting to appear a safety freak please remember electricity is
dangerous and should not be handled without proper care.
It seems you are flaunting most rules using a spare core and common neutral.
Most external systems are connected by a double pole switch or breaker and
when switched off disconnect both live and neutral cables.
This would account for your neutral fault but more importantly make the
neutral wire LIVE if connected to an appliance pluged into your new outlet.
Consider scrapping the idea and fitting a weatherproof socket to the pump
.Then you could unplug it and use the socket for your appliance.
Whatever you decide please check with an approved electrical installer if in
doupt and consider ELCB or RCD protection for the outdoor circuit.
Your idea of using a weatherproof socket which the pump could use is a good
idea and the socket could be used for short periods when I require power for
Actually I already have fitted a weatherproof socket and also the circuit is
protected by an RCD.
Thanks for the advice.
Further to my reply I have now realised that I cannot utilise the pump
circuit because it is controlled by a pressure switch so that the circuit is
only live when water is required and the pressure drops.
So I will have to abandon my idea.
As I explained previously - all you have to do is slighlty re-arrange
the wiring. The pressure switch is bypassed so as to provide a
continuous supply at the remote end, that can be used for the pump and
anything else. You then connect the pressure switch to the spare core
and use that at the remote end to operate a relay/contactor - which
controls power to the pump.
Thanks for your help. For some reason I did not read your email of the 9th
which gave this information. Sorry. But I will now have to draw a wiring
diagram which will help me understand the solution.
I assume that you are resorting to this because the pump power is
switched at the house?
If so, I would re-arrange things to use the existing cable to supply a
permanent power supply to the pump end. You can then power the pump and
anything else from that permanent supply.
That just leaves the problem of switching the pump on and off..
You may be able to use the spare core, correctly fused, to control a
relay at the pump end, subject to the regulations for your locality.
However, if not, no problem. You can superimpose a control signal over
the wiring, if that is allowed (which I would hope it would be) or use a
wireless solution for the control signal.
As far as the control of the pump, it is controlled by a pressure switch on
the water supply in the house. When a tap is turned on the pressure drops in
the system until the pressure reaches the setting for switching on the pump.
There is also a pressure bag which keeps the pressure in the system at a
level so that when the tap is turned on initially it starts the flow without
I therefore cannot change the system or don't want to change the system.
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