POwer testing in old house

UK electricity can be 'interesting' - We have three phase power, 415V (EU 400V) across the phases, so shocks are pretty disastrous. Not that long ago, we had a regulation that said that two outlets in a space could not be closer than 6 feet if they were on different phases! Then we got rid of that regulation and now we can have that 400+Volt difference a hand span apart. Luckily, in homes at least, more than one phase is very rare. On stage, it's very different. Three phase power is common and most, but not all people have a healthy suspicion whenever they see red coloured connectors rather than blue!
 
Was going to say! GEEEEZ! wire nuts and tape! The things you can get away with using 115volts! (but I still wouldn't)

Here it has to be covered junction boxes with meaty copper screws (about M6, bigger for higher current devices)

I am not a qualified sparks but I do know our systems are VERY conservatively rated. Electrically started fires are pretty rare and when they do happen it is almost always the punter doing something stupid. In fact, with the now almost total indoor smoking ban, fires of any sort are much rarer than when I was strippling.

Dave.
 
Back in the 60s/70s it was quite common for us to use those porcelain twist on joiners - you'd twist the conductors, screw the gizmo on and that was that. Then these became BAD things, and we have just started to use them again.

In the studios here everything is fed from two circuits on the consumer unit and the ground is common to every circuit. I'm considering a totally separate building out the back, and if I go ahead, our current regs will mean that we use armoured twin core for the Live and Neutral, with the wire screen grounded at the consumer unit but NOT attached to the new building's ground. This will be an earth stake, giving the new room it's own separate ground. I'm very concerned that any audio or video links I take to it are going to be potential problems. So it might be a real pain. I don't think you have this in the US electrical code (is that the right term?) Our system means that the main part of a building is a zone where ground is always the same potential. A new, separate building is not in this zone, so becomes a totally new one.

I have a tube Laney guitar amp, and this is extremely prone to ground issues - no idea why....... yet.
 
Rob, be very careful that the earthing arrangements you propose meet regulations. In any case, there might be a better, lower noise way to do it.

There is a guy, Dan Mills over at SoS forum who knows EVERYTHING there is to know about PME and other grounding systems. I suspect he will say, "Yes, you can have a earth divorced from the utility but better to bury multiple plates/screens than rely on a stake.

The Laney amp? You MUST have the incoming mains earth straight to chassis of course but the "earth" side of the HT can go to chassis via back to back diodes a cap and resistor. The problem will probably be too many ad hoc connections to chassis about the circuitry. Is the Laney really fussier than other amps? If so I would love to now how one of "ours" fares!

Dave.
 
The other thing about using an earth stake is that how effective it is depends on the state of the soil you're driving into. Many years back I was working on a medium-large TV installation in central London and we originally specified an earth stake for the tech earth. However, after some calculations it worked out that we'd need a massively deep stake to get the impedance as low as we needed.

We ended up bringing the earths from all technical equipment back to an isolate earthing bar and from there we used some huge cable to run it back to the power company earth (LEB in our case). This gave us the necessary low impedance with all tech gear earthed to a central point and isolated from all the building/office stuff.

As far as phases, the numbers worked out close enough that we could have studio lighting and air conditioning on one phase, all tech gear on another and the rest of the building on the third. Of course it was big enough that our supply was 3/4 of a megawatt. I'm glad I only signed the bill and didn't have to pay it.
 
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