lost neutral damage

Robert Turnbull · Apr 8, 2013

Had a call from a friend who does commercial kitchens, mainly duct work and extract fans. He was at a job to look at a faulty fan.

He called me said he plugged in his drill and it started making a funny noise and the lights were flicking.

He said a there was a sparky next door so I advised see if he could check for a neutral. And to unplug and turn off everything.

There wasn't and seams appliances have been damaged.

Would it have caused damage to the actual installation, they have asked for a price to check it out sounds like about 30 circuits over 2 boards. My friend had left so was a rough guess.

I was going to price for a full ECIR

But that's a fair bit of work and wondering if it actually warrants it

Rather than some time seeing what's damaged and what's not.

Marvo · Apr 8, 2013

It's highly unlikely damage was caused to the installation although a loose neutral connection may have burned the neutral wire or the termination itself. Damage would have occurred to single phase and possible 3-phase appliances because one of the phases would have elevated in voltage. I'd test the appliances for damage rather than the installation.

Robert Turnbull · Apr 8, 2013

Sorry should have noted floating rather than lost, was from the supplier, there was 400v showing from L-N

This is all info passed to me over the phone, but some appliances were smoking before unplugged

Darkwood · Apr 8, 2013

If the neutral has been lost in a 3ph system then yes equipment rated at 230v will have had up to 400v and thus damage could be extensive on any items connected, you need to find the cause of the neutral issue so as to afford blame... if its a DNO problem then they could be liable for the costs although if its due to theft from the substation then they wont cover you for any damage. If the issue is due with-in the customers installation then hope they have insurance.

Robert Turnbull · Apr 8, 2013

As far as I know it was supply side as next door was having issues also.

I don't know if it was a 3 phase supply but as its a commercial property I assume it is

Darkwood · Apr 8, 2013

The DNO's transformer is 3ph if its lost anywhere on there side then even though your installation might be single phase it will be subject to the damaging voltages and if other premises are effected then the customer needs to get in touch with them and approach the DNO as one group to re-enforce the claim........ but as I said earlier the main cause of this is usually cable theft from sub stations and because this is a criminal act it means the DNO are not liable as they are not at fault unless the substation wasn't secure.