Installation on ring mains

[rowan.bradley]

I have been chatting to Support today about an issue that I have with my Vue 2. I have sensors on all my circuits apart from Smoke Detector, Burglar Alarm and one lighting circuit. I am getting Balance readings of about 380W. It’s difficult to believe that these three circuits are using 380W. The support guy (who I suppose was in USA) told me that for ring mains I need two CTs, one on each end of the ring main. I asked him why simply putting both wires through one CT was not good enough, and he said “it confuses our sensors”. Do other UK users wire ring mains with 2 CTs each? Can anyone explain why this is necessary? Maybe Emporia head office doesn’t realise that ALL UK socket are (have to be, according to the IET regulations) connected to ring mains.

Thank you – Rowan

[Ralphg]

I only have one CT clamp on each ring.  I’m not even sure if its possible to get 2 clamps on a single circuit.  I have clamps on all my circuits and I still get a balance of around 20-40w, or around 390wh per day.  Oddly, the circuits for the smoke detectors and Emporia have never recorded any power consumption.

[jj613]

I don’t know if this is allowed in your country but perhaps rather than putting the ring ends directly into the circuit breaker, you could join them in a separate lever nut, and use a short, suitably sized tail wire to the circuit breaker, then put the CT on that tail?

• This reply was modified 2 years ago by jj613.

[Azazel1024]

I still haven’t figured out the floor of sensitivity for the regular circuit CTs, but mine don’t seem to start reading anything until the power jumps above maybe 5 watts on a circuit. It seems fairly accurate above that level, but if below, nada. For example, my heat pump water heater reads as 0, despite the fact it is obviously sitting there on, but not running the heat pump. Near as I can figure using another clamp meter and other’s feedback, I think it draws around 2-3w. Similar things like having a phone on a charger on my washing machine circuit it shows 0W, but pretty sure it is pulling around 3w. Having the washing machine on, but not running, shows 0W. Pretty sure its drawing at least a watt or two for its electronics. The zone valve controller for my heating system shows 0w when on if nothing else is on, on the circuit. The oil boiler draws about 8w on, but not running (and circulators off). With it on and the zone valve controller on, it draws about 13w. So pretty sure that the zone valve controller is actually drawing around 5w, but the initial sensitivity is too low to show up until there is slightly more load on the circuit.

I am wondering if that might be why Ralpphg, you might see a balance of 20-40w. Is circuits showing 0W, but actually there are some lights draws of a few watts that the sensors aren’t picking up till there gets to be more load. Combined with probably none of the sensors are 100% accurate, so a .1-.2% inaccuracy across various CTs can add up to show a slight imbalancee.

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