Electrics - Main Switch vs Meterbox Isolation Switch

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mattwnz

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#249460 12-May-2019 01:09

My parents have had a meterbox and distribution board installed on a new home. The meterbox is installed directly below the distribution board, as shown in the photo below, on an internal garage wall. The distribution board contains the fuses, RCDs etc. Also installed inside the distribution box is the red triple switch the electrician has named the 'main isolating switch', and the white switch (which doesn't match the others), is named the 'main switch'. (as shown in the zoomed in photo inside the distribution box below)

The meterbox below the distribution board contains the smart meter, and the 3 red things are the surge protectors.

Initially the electrical inspector wasn't going to allow the electrician to install the meterbox in this lower position. I can't remember the exact reason, but it was something to do with the regulations not allowing a switchboard, or a board containing the main switch, to be lower than a certain height above floor level. However checking with our power companies technical manual and their staff at the time, the power company said they did allow the meterbox to be at this lower height. From memory the meterbox is currently about 1.2 - 1.3 metres from the floor. The power company said that we needed to tell the electrical inspector that the meterbox is not considered to be a switchboard, and the switch inside the meterboard box is an 'isolation switch' for the purpose of allowing a meter reader to isolate the power, and that it is not the main switch. The main switch would be inside the distribution board, which I presume would be the red triple one.

Despite telling the electrician all this, the electrician still moved that switch out of the meterbox, into the distribution box above.. The switch that was moved, is the one that he has named 'main switch', and is the one that doesn't match the others in the distribution box. The question is, is that switch that the electrician has moved and has called the 'main switch', actually considered to be the meterbox 'isolation switch', or is it possible that the electrician has wired it up differently to how it would normally be wired up? It is on triple phase power which may make a difference. We had a sales rep for one of the switch companies view the boxes, and they said they had never seen the switch (the one the electrician has named 'main switch'), installed in the distribution box like that before.

If they have installed the meter 'isolation switch' in the distribution board, then is the 'main switch' actually the triple red switch in the distribution board, that the electrician has named the 'main isolation switch'? We are just trying to get our heads around it, and ideally wondering if they could have just left the switch in the meterbox, instead of moving it into the distribution board above, if they had just named it 'isolation switch'. If the meterbox normally has an 'isolation switch' , shouldn't there be something to isolate it inside the meter box ?

Aredwood

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#2235214 12-May-2019 01:39

So does the power first enter the top switchboard, go to the meter board, then back to the switchboard again?

Why didnt the sparky just install the meter in the switchboard? Instead of trying to apply a set of rules that were intended to cover the meter and switchboard being in different locations.

And is the box with the electricity meter a metal box? Next issue will be the power company complaining that they cant remotely read the meter as they cant communicate with the meter. And when they send a meter reader to your house, the meter is inside your house.

My understanding is that the power companies also use the smart meters as part of outage monitoring. And they therefore dont like people turning off the power upstream of the meter. As they then have to guess whether a meter losing power is an actual fault or not.

Aredwood

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#2235217 12-May-2019 01:57

Is this the same house as in this thread?

https://www.geekzone.co.nz/forums.asp?forumid=141&topicid=239358

If so, then the meter isolating switch will be there due to what that inspector said.

mattwnz

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#2235218 12-May-2019 02:07

Aredwood: So does the power first enter the top switchboard, go to the meter board, then back to the switchboard again?

Why didnt the sparky just install the meter in the switchboard? Instead of trying to apply a set of rules that were intended to cover the meter and switchboard being in different locations.

And is the box with the electricity meter a metal box? Next issue will be the power company complaining that they cant remotely read the meter as they cant communicate with the meter. And when they send a meter reader to your house, the meter is inside your house.

My understanding is that the power companies also use the smart meters as part of outage monitoring. And they therefore dont like people turning off the power upstream of the meter. As they then have to guess whether a meter losing power is an actual fault or not.

Thanks, some interesting points there.

I think they didn't install it in the switchboard above because of the size, as the current distribution board is nearly full, and that was the largest size they do of that particular box.

I know the main power cable comes down from the top of the wall. The electrician apparently said the white main switch will shut off all the power including to the meter. So I assume it is between the main electricity feed coming into the building, and the meter. So if it does, then it potentially could be detected as a fault? Apparently the red main isolation switch will just shut off power to all circuits inside the distribution box, but it won't affect the meter. If the meter normally has an isolation switch which only turns off the power going through the meter, couldn't people just turn the meter off and get free power?

The meterbox is a typical metal one. I am surprised they haven't put one of the small aerials on the outside of it, although the smart meter I have at home is also inside a metal cabinet and doesn't have one, but my one is on an exterior wall. This one is inside on an internal wall so will be interesting to see if they do have problems with getting a reading on it.

Aredwood

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#2235219 12-May-2019 02:23

Is there an actual problem you are having with this? Apart from the annoyance of the politics of it all.

Since the power goes through the meter, turning off the meter isolation switch also turns off the power to the whole house. So that by itself wont get you free power.

Since you also have those surge protection units installed. Leave the meter isolation switch turned on. And only turn off the main switch. If you are turning off the power for whatever reason.

gregmcc

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#2235226 12-May-2019 07:34

From a regulation point of view there is no need for the 1st main switch before the meter - in this case the ugly surface mounted one that doesn't match the rest - this is simply the power company imposing their own rules.

The main switch should have been mounted on the meter panel and no main switch on the distribution board, no actual reason to have a 2nd main switch in close proximity, but saying that, there is nothing wrong with having 2 main switch as per the current setup, it just adds confusion to how it actually works.

mattwnz

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#2236343 14-May-2019 02:05

Aredwood: Is there an actual problem you are having with this? Apart from the annoyance of the politics of it all.

Since the power goes through the meter, turning off the meter isolation switch also turns off the power to the whole house. So that by itself wont get you free power.

Since you also have those surge protection units installed. Leave the meter isolation switch turned on. And only turn off the main switch. If you are turning off the power for whatever reason.

Thanks. There are a few problems due to it’s current positioning. Firstly having that additional switch is using up space in the distribution box for future additional work, as the spec says it needs at least 20% of free space remaining in the box, and the switch appears to prevent this.

I can also see a potential safety issue associated with it, due to the potential confusion it causes, as it is not a normal place for the white switch to be. I am guessing that the white switch if it was in the meterbox, would have been labeled ‘isolation switch’, which allows a meter maintenance person to isolate the meter from the mains power. But because it is in the distribution board, they have labeled it main switch . However in the distribution box, the red switch is labeled ‘mains isolation switch’, so potentially someone could read that, and think that is the switch they need to turn off to isolate the meter, and not notice the white one which is recessed in the box. But the one label ‘mains isolator switch' will only isolate the distribution box from mains, and not the meter box and surge protector below it.

The surge protectors in the meter box below also say to ‘make sure you turn off the mains in the switch box ‘above before servicing them, but there are two mains switches, and only one will supposedly isolate the surge protector from mains. You would hope any electrician servicing it would pick up the two switches in the distribution box above, but things can be easily missed.

The other thing that the switch rep noted, was that there is a gap around the outside the white 'main switch, as it isn’t designed to fit inside this type of distribution board. So it is not protected with blanking plates to stop fingers getting in behind it, where there are potentially live wires.