Power meter cabinet - what does each wire do?

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EB255GTX

36 posts

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#2959860 26-Aug-2022 16:03

decibel:

So - what EXACTLY is the difference between Spyware's Centameter and KooKoo's unit?

Exactly? Many details from price to colour to the way the data is displayed.

But broadly, they are both home power meters, with wireless link between the sensing part (CT) and the display. Some have a small LCD display for data, some have a browser web interface for data... They are the same type of device.

decibel

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#2959883 26-Aug-2022 16:13

EB255GTX: Neither the clip on or light sensor type are “outlawed”, but to the letter of the law they should be installed by a sparky as they will both be in the meter box.

What then, about rewireable fuses? Depending on the installation, they maybe "in the meter box" and when the fuse is removed, a terminal is exposed which is at full mains voltage?

decibel

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Ultimate Geek
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#2959885 26-Aug-2022 16:13

EB255GTX:

decibel:

So - what EXACTLY is the difference between Spyware's Centameter and KooKoo's unit?

Exactly? Many details from price to colour to the way the data is displayed.

But broadly, they are both home power meters, with wireless link between the sensing part (CT) and the display. Some have a small LCD display for data, some have a browser web interface for data... They are the same type of device.

Right, so the Centameter is legal, but Kookoo's unit is not? Why exactly is that?

EB255GTX

36 posts

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#2959888 26-Aug-2022 16:17

decibel:

Right, so the Centameter is legal, but Kookoo's unit is not? Why exactly is that?

No, neither is legal for a homeowner to install if you take the letter of the law - per this post:

"Neither the clip on or light sensor type are “outlawed”, but to the letter of the law they should be installed by a sparky as they will both be in the meter box. "

EB255GTX

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#2959895 26-Aug-2022 16:20

decibel:

EB255GTX: Neither the clip on or light sensor type are “outlawed”, but to the letter of the law they should be installed by a sparky as they will both be in the meter box.

What then, about rewireable fuses? Depending on the installation, they maybe "in the meter box" and when the fuse is removed, a terminal is exposed which is at full mains voltage?

See earlier up this thread - the rules say you are not to enter the enclosure, or put yourself in a position to touch live terminals. So again, letter of law - you'd call a sparky to replace the fuse. Is that realistic, or what happens? No, but that's up to the individual.

gregmcc

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#2959910 26-Aug-2022 16:37

decibel:

EB255GTX: Neither the clip on or light sensor type are “outlawed”, but to the letter of the law they should be installed by a sparky as they will both be in the meter box.

What then, about rewireable fuses? Depending on the installation, they maybe "in the meter box" and when the fuse is removed, a terminal is exposed which is at full mains voltage?

You will find this type of meter box (usually) has a full panel which covers all cables that have primary insulation, and are not screwed shut.

Yes when the fuse is removed there is a bare exposed terminal, that was the 1970's standard, things have moved on in the past 50 years, while still legal to use ones installed many years ago, it is not legal to fit them as a replacement or new item.

Not to mention they have a bad habit of shattering under fault conditions.....

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decibel

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#2959947 26-Aug-2022 18:14

So which is more dangerous - replacing a rewireable fuse where an exposed terminal is at full mains voltage or placing a clamp on an insulated conductor?

EB255GTX

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#2959950 26-Aug-2022 18:20

decibel:

So which is more dangerous - replacing a rewireable fuse where an exposed terminal is at full mains voltage or placing a clamp on an insulated conductor?

I'll give you a question in return. Would you be more comfortable with the possibility of coming into contact with around a) 230V, or b) around 3000 to 5000 volts? Because if you think b) is more dangerous, then I'll answer "placing a clamp on an insulated conductor" to your query :-)

Another way of looking at the scenario is - would you be more comfortable replacing a fuse where it's very unlikely that any equipment will be damaged by doing so, or would you place a clamp on an insulated conductor if you knew there was a risk of damaging the monitoring equipment you just purchased?

It's not always the obvious answer with electricity you see, which is why the rules are in place.

Tinkerisk

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#2959970 26-Aug-2022 20:07

Fortunately, at least this is not a TN-S power connection. At least a few laypeople still have respect for that. 😋

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prevaljo

177 posts

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#2960557 28-Aug-2022 20:24

I think this is a really great thread, I haven't read every post but I'm sure I would have caught a reference to the following. When the public were sold the concept of a "Smart" meter I for one naively believed that we would be getting the ability to display in real time electricity usage, but no, what we got was the fact that the electricity companies no longer needed to employ a meter reader, and some old data on a website. I'm sure I've seen pictures of homes in the UK with a smart display showing real time costs and usage but maybe not.

tripper1000

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#2960766 29-Aug-2022 13:31

@KooKoo

Either of the fat red wires should work fine. One is the feed in to the meter, one is the feed out. If you find the CT isn't detecting your hot water usage, shift it to the other fat red wire. If your current readings are backwards, (ie reading generation instead of consumption) the wire is going the wrong way through the CT so just flip the CT 180 degrees.

The black box to the lower right is a pilot relay - it switches your hot water on and off (and maybe other loads like like night store heater or spa pool). It is remote controlled by your lines company via white wire. (these superseded "ripple" control in some areas. This can instead be controlled via the meter and not the white wire in some jurisdictions). The red wires into it are the metered power supply in to the relay and hot water feed out of the relay.

The black wires are neutral supply to the meter and relay and have negligible current through them. Your CT doesn't won't get useful readings on these.

Don't worry about the internet police above. Provided you don't go anywhere near the wiring with tools you are legally fine (ie never put put tools to terminals or cutters to conductors).

In terms of sensible risk mitigation, a good rule of thumb is to only ever put one hand into a box like that (keep one hand in your pocket) - that way if someone has carelessly left a conductor exposed, the shock you get is not from from hand to hand and through the chest. It's also a bad idea to be wearing bare feet, and don't go in there when the floor is wet, and don't use a metal ladder to access it - these things unnecessarily increase the risk from shocks. Take a good look in there first before sticking your fingers in. Look for exposed copper (that is not associated with earth terminals). Look for insulation cracking, crumbling or melting from old age - if you see that, you need a pro. The only copper I can see in the photo is the earth terminal which is OK. Avoid yanking on the wires. If you need to separate wires to make space for the CT, use a non-conductive stick like a plastic pen to push the wires around. That way if there is insulation missing, say on the back side of a wire that you can't see, or if the insulation crumbles when touched, you can't inadvertently touch conductors and get a shock.

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EB255GTX

36 posts

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#2960768 29-Aug-2022 13:44

tripper1000:

Don't worry about the internet police above.

.....but DO get your electrical safety advice from internet strangers?

Tinkerisk

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#2960793 29-Aug-2022 15:36

It is quite courageous to post an electrical procedure instruction from a layman to another layman in writing on the Internet. The question of recourse in the event of damage would thus be clarified. :-)

Speedy885

182 posts

Master Geek
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#2960910 29-Aug-2022 19:27

Its the old, if you have to ask, probably shouldn't be doing it sorta thing. This thread could go on for 50+ pages with everyone throwing their 2c in and possibly confusing people even further. One should study things like this from appropriate Literature and then make an informed decision about what they are doing. If you CBF, then you pay someone to do the job for you.

MadEngineer

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#2960916 29-Aug-2022 19:50

Kookoo:
EB255GTX:

Where's the other end of the CT wire during this process?

It's attached to the radio module which sits outside the meter box.

fantastic. You’ve run a conductor from inside the meter box to the outside of it. Think about that for half a second.

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