Earthing

[Dave A]

Not that long ago we had to go out to a house with a three phase supply where all hell had broken loose. Turned out there had been a cable theft, and the municipality had crossed the neutral with a phase when replacing the cable.

Actually, I wonder how their claim against the municipality went? I probably should give them a call.

[AndyD]

I've seen a few rough installations done by the council and Eskom but thankfully I've never heard of this happening. Anyone doing the same with a 1000Amp commercial supply would only do it once. On the rare times I've not been happy with something and logged a complaint they've always made good and in reasonable time.

I've seen damaged cause on three phase systems by a 'missing' neutral fault. When the neutral is allowed to float it's voltage follows the highest loaded phase so single phase equipment on the other two phases receives 380volts. It can cause a lot of damage to appliances.

[bergie]

i've heard of a few times where council have connected 380 volt to a single phase supply. they have insurance ,so they pay quick. incidentally today someone told me that there neighbour who didnt have power for a while(smallholding) had there power reconnected this week and a lot of electronic appliances were blowing up. smoke coming out of the dvd player,etc. i told them to report it to eskom straight away.
re the earthing:there are quite a few overhead supplies still around in the older parts of cape town.there wouldnt be a supplied earth,only the spike.

[AndyD]

there are quite a few overhead supplies still around in the older parts of cape town.there wouldnt be a supplied earth,only the spike.

I assumed there might be from some of the fault descriptions I've seen posted. My experience of domestic installations is very little. When no earth is supplied then the spike impedence values are critical, also a nice deep spike is essential for sseasonal stability.

incidentally today someone told me that there neighbour who didnt have power for a while(smallholding) had there power reconnected this week and a lot of electronic appliances were blowing up

Ths made me smile because it reminded me of an audio clip called 'Melk Boer' someone emailed me a few years ago. It was a recording of a melk boer who phoned Eskom with a complaint about his motors being trashed by the power linesmen workng on a power pole. I'll see if I can find it.


*Edit* Link (not family friendly...you've been warned!!!!)

[Phillip Armstrong RTB]

Is there anything such as an Earthing Certificate? I have an Engineer asking for Earthing Certificates for various office buildings that fall under his care. As far as I know it is not a requirement to earth steel roofs if the supply is an underground cable. I agree that all Earth Bonding is necessary ( Geysers; steel light fittings; etc. ) As for the normal COC the Earth Loop test and Neutral Loop test would be done.

[Derlyn]

Is the engineer licenced and registered ?

[Isetech]

You would need to get a company which specialises in earthing and lightning protection to carry out a risk assesment.

Is there anything such as an Earthing Certificate? I have an Engineer asking for Earthing Certificates for various office buildings that fall under his care. As far as I know it is not a requirement to earth steel roofs if the supply is an underground cable. I agree that all Earth Bonding is necessary ( Geysers; steel light fittings; etc. ) As for the normal COC the Earth Loop test and Neutral Loop test would be done.