I've read this piece on the website of a local paper:
'All properties in the UK have electricity supplied at 240 volts. However, without copper earthing, this can soar to 400 volts'.
Any ideas?
415v between phases, 240 phase to neutral. The neutral is bonded to real earth at the substation. Remove that bond and weird things can happen depending on how well balanced the load is on the 3 phases. It may also be influenced by how the loads are connected, delta or star. That is about the extent of my 3 phase knowledge, someone will be along in a while with chapter and verse.
It's neutral, not earthing, links that are being stolen, AFAIK. Each outgoing circuit will have three line fuses and a solid neutral link, the last being removable for complete isolation. Take away the neutral bond on an unbalanced 3-ph 4-wire circuit and you unbalance the phase voltages, some rising and some falling, wrt the now-floating neutral conductor in the cable.
Pikeys
In Norway there is no Neutral. Everyone gets three phases and the sockets in each room uses two of them. there is 220V between the phases. there's a fuse in each of the three.
I was told the reason was to reduce the maximum voltage relative to earth.
if you blow one fuse then you end up having some rooms with their sockets in series with the sockets in another room - turn on the heater in one room and the TV comes on in the next room etc.
Robert
Part timer explained :
All supplies are 415v 3 phase, which is 415v measured from any phase to any other phase. The 240v is derived by connecting from any one of those phases to a Neutral wire which is effectively the ground/ earth connection at the sub-station. Basically, the idea is that all of the
240v supplies should be equally balanced loads on each phase, so that no current flows down the neutral. Now if someone removes that bit of bus-bar which connects it to ground and should the 240v supplies happen to be badly balanced, then that 240v can rise upto the phase to phase voltage of 415v. So instead of the 240v a domestic consumer might get normally, they get 415v instead.
Is there a reasonable chance that something would burn out and (hopefully) trip the mains switch?
It happened to a housing development I was in 25 years ago. Builders dug through the UG cable neutral and left 400 v on some flats due to unbalanced load. Midlands Electric, as it was then, replaced a large number of TV's, kettles,fridges, heaters etc. etc. which went up in smoke and flames. No one injured fortunately.
rusty.
We had a copier burn out at work one night, due to some ill-executed site electrical maintenance. Luckily the smoke was spotted before it took the building with it.
Chris
I've noticed that the copper lightning earth's at communication sites are now being replaced with Ally and signs to the effect of "No Copper on this site" are starting to appear..
Taking the Sky box first - so not all bad.
Alpha mark to Adam.
(He would have merited 'Alpha +' for "pikeys, and our best hope is a genetic engineering solution")
That's 3-ph 3-wire rather than the more usual 3-ph 4-wire. The downside is the low line voltage 230 V rather than 400, so currents are higher.
Do industrial & commercial premises get the same, or a higher voltage?
Isn't it an IT system too? How are earth faults detected and cleared?
Linked 3-pole MCBs would prevent that.
Sounds like a different sort of copper is called for...
Do what I did a few weeks ago, phone 999 and have the idiot arrested. Call the network operator too as the police won't enter the substation.
I have identified the problem. YOU suggested the solution, is it your own idea?
You got yourself arrested?
And it was a first class solution.
Ummm - I'm not sure - I think that Austrian bloke who was painter in the
1910s might have had it first. But I don't want to be a DIY China syndrome so I hope it's OK if I (i) stop digging and (ii) go to the pub.
Bugger - I meant of course a first class identification of the problem.
(Why didn't SWMBO look over my shoulder sooner? Why doesn't the toast know to land butter side up? Why doesn't Pi = 3? .........)
You could blame the Jews:-)
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