Question for a Electrician

[jamesrose]

Hi, just looking for a bit of advice from a sparky if anyone would be so kind...

Here's the story..

An electrician came over to my house which I have just moved into to wire up some strip lights into the garage. There was already power and a single lightbulb in the garage which all appeared to be functioning ok, as far as I could tell.

The guy installs the lights and everything seems fine until he is testing the circuits afterwards. He tests the circuit which trips the RCD in the house 4 times as intended to check that that is working. He then tells me that at the main switch on the garage wall there is a reading of 54 Ohms and this is way to high. He thinks there is a problem with the earth and tries to find the power feed to the garage from the house which can't be located and apparently doesnt run from the consumer unit.

It sounds like the options are to relay a new cable to the garage, or an earth rod in the ground near the garage.

I have a pretty limited knowledge of this kind of thing so just wanted to check that this all sounded above board. He seemed like a decent guy, but I wanted to check before this goes any further...

Many Thanks

[headcase]

A reading of 54 ohm across a switch is far too high, should be 0 ohm when turned on but this signifies a faulty switch not a faulty earth. Or is he measuring the resistance of the earth connection?

[Brite spark]

jamesrose said:

An electrician came over to my house which I have just moved into to wire up some strip lights into the garage.

has all this been done by an electrician or a domestic installer/ are test certificates being supplied, and all work in accordance with part p?

jamesrose said:

He then tells me that at the main switch on the garage wall there is a reading of 54 Ohms and this is way to high.

Do you know if this was a live test (eg, zs or elz) or a dead test (eg, r1+r2), ie live or not? Depending upon what he has tested it may be an acceptable reading, was it 54 or 0.54- find out what test he was doing if you can

jamesrose said:

He thinks there is a problem with the earth

- Personally I would want an answer more difinitive than I think

jamesrose said:

...and tries to find the power feed to the garage from the house which can't be located and apparently doesnt run from the consumer unit.

The power may not run from the consumer unit- he may not of physically located the cable but should of been able to work out which circuit it was on by either turning breakers on or off one at a time, until power was lost/restored

jamesrose said:

It sounds like the options are to relay a new cable to the garage, or an earth rod in the ground near the garage.

The garage really wants its own dedicated supply adequately protected from the consumer unit if it isn't already

jamesrose said:

I have a pretty limited knowledge of this kind of thing so just wanted to check that this all sounded above board.

not really enough information

jamesrose said:

He seemed like a decent guy,

so did harold shipman

jamesrose said:

but I wanted to check before this goes any further...

if in doubt get a second opinion- preferably from someone recomended

Edited by Brite spark on Tuesday 15th September 22:04

[JERRYCO]

Sounds like damaged insulation causing an earth leakage across neutral and earth. Maybe he should retest his insulation resistance. This should have already been done before energising the circuit though. I'm not convinced that he has followed all testing sequence! Do you have test results? Is he fully qualified?

[spikeyhead]

If the spark has tested a circuit in the garage that has tripped an RCD in the house, then surely he can find where in the house it is connected to jsut from tracing from the tripped RCD.