Is this an acceptable means of earthing ?

[Modster]

think you'll find out when you do a Ze as per my last post.

Key meter is currently £200 in debt so cant do ZE until its cleared

 

[dez0178]

Hello all,

I am doing a consumer unit upgrade for a family member in a domestic household, However i am unsure if ther earthing arrangement is up to scratch, As it is, the main eartghing conductor is clamped onto the incoming supply conduits. Southern electric have been and installed a key meter with the installation as it is, I am jib approved electrician, but im from an industrial background, Any advice from any of you guys would be greatly appreciated. I have attached some photo's for your perusal.

View attachment 34360

I work for the board, and cables like that ran in conduit are usually VIR or like someone on here has said flat lead , possibly. Usually the conduit runs next door, where their cable will be fed from there cut out. Maybe next-door has a pilc cable and they have took an earth from the pilc to the conduit to give them an earth. But not good, but a means of supplying an earth though non the less. Check next door. Do an earth loop to the conduit and see what the ze is? Looks like they have PME,d it anyway. Look at the earth cable it runs into the cut out, will most likely be terminated to the neutral block inside. A TNC-S system by the looks of it. Will need to check it though. Contact the board if in doubt. Hope this helps

 

[westward10]

This is possible but there appears to be no earth coming from the head in the second picture.

 

[Pat H]

Also shouldn't the earth wire on the first clamp be looped through under the screw. Not cut ends?
Not acceptable to loop (on my elec course) bonding with a cut cable.
But if the 1st pipe is actually the earth then its one cable to feed earth to the house and the second is the only bonding?
Does that make the pipe a MET

 

[7029 dave]

This is possible but there appears to be no earth coming from the head in the second picture.

looks like it to me.

 

[dez0178]

This is possible but there appears to be no earth coming from the head in the second picture.

It is terminated in the bottom of the neutral block, not at the head, like we see most of the time. We have terminated a load like that. But will have to verify that it definetly the case.

 

[dez0178]

Also shouldn't the earth wire on the first clamp be looped through under the screw. Not cut ends?
Not acceptable to loop (on my elec course) bonding with a cut cable.
But if the 1st pipe is actually the earth then its one cable to feed earth to the house and the second is the only bonding?
Does that make the pipe a MET

Yep, an M.E.T, in other words a Main earth terminal.if the ze is okay, but it is properly connected to the possible pilc cable next door? I've seen a few like this.

 

[westward10]

Your explanation is highly possible but where is the earth from the head to the consumer.

 

[LeeH]

Would the 951 clamp comply even if the conduit was the DNO's earth?

 

[7029 dave]

Your explanation is highly possible but where is the earth from the head to the consumer.

Yep give you that looks like zero , so he can bust into that earth lead an block it.

 

[7029 dave]

Your explanation is highly possible

 

[Modster]

Many thanks for your help with this guys,

Think ill get the DNO to come have a look just to clarify

 

[Leesparkykent]

Also shouldn't the earth wire on the first clamp be looped through under the screw. Not cut ends?
Not acceptable to loop (on my elec course) bonding with a cut cable.[/B]
But if the 1st pipe is actually the earth then its one cable to feed earth to the house and the second is the only bonding?
Does that make the pipe a MET

No its not a reg just considered best practise.

 

[polo1]

We have lots of supplies like that around here. Main tn-s supply into one property, then looped with vir tails in conduit to the next property. Main earth is taken from the first property via the conduit, to the second property. In fact I've been at two jobs in the past week both with exactly this arrangement.

 

[Pat H]

Why isn'ta 16mm earth run in the conduit as well? Copper would ge better than steel with 2 clamps involved.

 

[Lucien Nunes]

Because it was done in the era when nobody ran a copper earth or CPC if there was a steel containment available to do the job, just standard practice. Perhaps it's time to rephrase the question: "If the DNO supply arrives through a steel conduit that gives a satisfactory Ze when tested, is it adequate to terminate the EC to it with a BS951 clamp and consider the installation properly earthed?"

BTW surely that G/Y cable goes behind the wood to the CU and not into the sealing chamber / cutout?

 

[westward10]

That is highly possible now I look again.

 

[Modster]

Again many thanks for your help with this guys,

I will carry out Ze test as soon as the debt is cleared and power is back on.

 

[davesparks]

What is the earthing system? Is it possible that the DNO have converted it to TNCS and that the earth connections we can see apparently coming from inside the cutout are actually just earthing the conduit?

 

[dmxtothemax]

When the instalation was originally done
that would have been considered as adequate earthing.
Is it considered that today ? maybe not.