Is this going to be costly?

[nads75]

We have recently had a fridge/freezer repair man come out and before he started work he checked the electrics by plugging a device into the socket in the wall. He then informed us that he should not be carrying out any work in our home as the ohms were too high!

the meter gave a reading of 2225 ohms.

I have no knowledge of electrics at all but this is obvioulsy not good. We do have a history of fuse box tripping in our home so ive always wondered if there was problem and now it looks like its been found.

can someone explain to me why this reading would be so high in laymans terms?

My house is over 100yrs old but was gutted 20yrs ago by a builder so im assuming all electrics were updated then.

Cheers
Nadia

 

[1john]

Post a pic of your electric meter, fuse box and surrounding areas. Does your electric come in over head?

 

[riveralt]

We have recently had a fridge/freezer repair man come out and before he started work he checked the electrics by plugging a device into the socket in the wall. He then informed us that he should not be carrying out any work in our home as the ohms were too high!

the meter gave a reading of 2225 ohms.

I take it he checked more than one socket - and did he tell you it was an Earth Loop Impedance reading?

I have no knowledge of electrics at all but this is obvioulsy not good. We do have a history of fuse box tripping in our home so ive always wondered if there was problem and now it looks like its been found
can someone explain to me why this reading would be so high in laymans terms?.

The Earth Loop Impedance is a reading that is used to determine how quickly your electrical protective devices (MCB fuses) will operate - the lower this reading is the better. You will have either a Supplier provided earth or you will have a spike in the ground on your property.

In both cases the reading is significantly over what is considered safe. For supplier provided earths you should be looking at single digit Loop Impedance figures of less than 5ohms and for the spike in the ground systems anything up to 1667ohms is allowed (provided you have RCD protection) but anything above 200ohms is considered a problem.

If this is a correct figure you will have to get an electrician in to determine what earthing system you have and where appropriate bring it up to the specified level.

 

[nads75]

electrics and fuse box

• nads75
• 13 Jan 2011
• 1

here is a pic of my electrics.

yup he did test more than one socket.

sounds like i need a guy out then

thanks for info.

Nadia

 

[riveralt]

From your picture it does look as if you have a TT earthing system (the one with the earth spike in the ground of your property) with Miniature Circuit Breakers and an RCD built into the main switch.

It is also possible that the earth you have is connected directly to your water supply as was the case several decades ago.

You have two choices:

You could speak to your Distribution Network Supplier (not necessarily the people you pay your bills to) see this map
//www.diynot.com/wiki/electrics:other:dnomap
and ask them if they will access and possibly upgrade your earthing system - they do not have to do this and they may charge you.

You could ask your electrician to install a new or additional TT system or repair what's there already.

Good Luck.

 

[nads75]

Thanks for all the info,

My husband has now taken a look at the wiring coming down from the PME box which he thinks might be the earth. Its running down the wall in trunking and ends on the cold water supply pipe running along the wall.
He is assuming that is the earth?
A couple of years ago the water board upgraded all pipework to the boundry of the property (our property shared its water with next door) and installed all new plastic piping, so maybe my earth now has nowhere to go? its just dissapating through the copper water piping?

If this is the case then im assumin that an electrician will just need to run the earths outside into ground?

what would the cost be approx?

 

[riveralt]

Thanks for all the info,

My husband has now taken a look at the wiring coming down from the PME box which he thinks might be the earth. Its running down the wall in trunking and ends on the cold water supply pipe running along the wall.
He is assuming that is the earth?
A couple of years ago the water board upgraded all pipework to the boundry of the property (our property shared its water with next door) and installed all new plastic piping, so maybe my earth now has nowhere to go? its just dissapating through the copper water piping?

If this is the case then im assumin that an electrician will just need to run the earths outside into ground?

what would the cost be approx?

From your picture it doesn't look as if anything is connected to the earth terminal on the PME box. There appears to be cable behind the PME box running to the Consumer Unit.

The cost of fitting a TT system will depend on the number of earth spikes and cable needed and the time it takes to connect to your Main Earth Terminal and then onto your consumer unit. You will also probably need your water and gas, if you have it, to have its (there) main protective bonding cables replaced if there are any there in the first place.

In broad terms around £200 - but get several quotes.

I would still speak to the DNO they may ugrade your earthing system for free, then you would only have to pay to have your main protective bonding upgraded - maybe £50/80.

 

[ban-all-sheds]

My husband has now taken a look at the wiring coming down from the PME box which he thinks might be the earth.

I was going to say, on looking at the photo, that I couldn't see an earth wire coming from the cutout.

Even though you've said one is there, I still can't see it.

Its running down the wall in trunking and ends on the cold water supply pipe running along the wall.
He is assuming that is the earth?

No - that's a main equipotential bonding conductor - see //www.diynot.com/wiki/electrics:main-equipotential-bonding

A couple of years ago the water board upgraded all pipework to the boundry of the property (our property shared its water with next door) and installed all new plastic piping, so maybe my earth now has nowhere to go? its just dissapating through the copper water piping?

No - you have (or should have) a PME (aka TN-C-S) supply, where the earth is provided via the supply neutral cable. See //www.diynot.com/wiki/electrics:earthing-arrangements

Do you have an earth conductor going to the consumer unit?

 

[nads75]

Looking at that diagram, we do not have that earth wire from the fuse box going to the pme box. but there is a cable coming out of the fuse box (twin flat no earth) horizontaly (on the pic i posted) into a seperate wall mounted box that has a fuse port inside and we dont know what that is?

So i t looks like all we need is that connection from the pme to the fuse box.
I will contact western power to see what they suggest before calling an electrician.

At least i understand some of this now so cant be bafled by the electrician.

Thanks everyone.

 

[SgtTrojan]

A very conscientious fridge man if you ask me

 

[ban-all-sheds]

So i t looks like all we need is that connection from the pme to the fuse box.

No - you need the whole installation inspected and tested.

Anybody who could contrive to remove the main earth cannot be trusted to have done anything right.