if mains severed by a jcb..

[consumer done over]

Would a property be at risk of fire even if there is no power due to a jcb severing the customer's supply?
I am assuming that on a TNs supply there would be no earthing.

Also after repairs could earthing levels protection have decreased as a result of the damage?

thanks

 

[Spark123]

If theres no power then I doubt there will be a risk from the electric. If the cable is open ended in a trench then that is another matter! It needs reported to the DNO as a matter of urgency.
On either type on TN supply the means of earthing would be cut.
It is up to the DNO to make it good again, this includes the integrity of their earthing.
And a matter of the JCBs insurance to pay for it!

 

[consumer done over]

so if cable is not completely severed and power is still on but earthing is compromised and the trench is covered up by cowboy contractors who may not even notice the problem you could have a supply which is dangerous without anyone knowing?

Does this happen often?

 

[RF Lighting]

No. The cable is designed as it is for this very reason.

You would not be able to sever all of the earth to the property without a big flash and bang in the trench.

If the cables has even been nicked though, you need to call the DNO immediatly, and have them inspect their equipment. They are the only people who can say if it safe or not, and do the repiar if it is required.

I expect they would probably dig out the trench at the expense of the JCB operator.

 

[consumer done over]

thanks.

in your experience as an electrician do you find that contractors are generally honest in owning up to mistakes such as cutting through cables?

Also do you know what distance are cables buried below footpath level?

 

[Spark123]

In my experience, if they can get away with it they will! Some even have the nerve to back fill the trench and leave a whole area without power in a poor effort to cover their tracks! This only serves to enlarge their bill as the DNO then have to start looking for the fault.
Sometimes honesty is the best policy, last time we went through a phone cable it cost us a cup of tea and a couple of rolls of insulation tape!
Cables should be low enough to avoid damage, there is a suggestion of 400mm below a path and 700mm elsewhere where digging can occur: clicky
Not sure what rules the DNO work to tho.

 

[ColJack]

the fun part is watching a jcb operator trying to short out the cable with the diggers bucket, to make the fuse blow so they can carry on in the trench..

my cousin in law did it once with a street lighting cable and it wouldn't short out... made a hell of a mess of the bucket..