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#142017 11/29/04 07:23 AM
Joined: Jul 2002
Posts: 8,443
Likes: 3
Trumpy Offline OP
Member
Now this is going to sound really weird to you guys, so bear with me.
I was talking to a former Electrician colleague of mine tonight on the phone, who told me about a job he has to go and do in the morning.
Apparently the customer wants to have a remote control switch installed next to his bed, so that he can turn off the power to his house when he goes to bed.
(I told you it was weird!) [Linked Image]
This won't be an easy task, considering that the switchboard is at one end of a large house and the bedroom is at the other end.
OK, what my mate wanted to know was this, is it possible to replace the existing main switch with a contactor?.
I said sure, but the supply for the control circuit would have to come from the Line side of the Contactor and that for a fact is something that I know you aren't allowed to do, fused or not. [Linked Image]
Any equipment here up to the Line side terminals on the main switch are Power Company property and they don't tend to like people (including Electricians) joining other wires onto thier Meter Tails, so I'm not sure how he's going to get around this one.
I have some reservations about using a contactor in the first place, in that what happens if the contactor welds itself shut one day (as contactors can do).
I'm of the opinion guys, to always give the customer what they want, as far as the Reg's allow, but surely there are limits?!.
How would you go about a mission like this?.
Oh and by the way, I'm told that this particular guy isn't short of a dollar or two.

Joined: Feb 2002
Posts: 183
N
Member
What about putting the contactor and fuse/breaker for the contactor's coil between the main and the rest of the panel? You might need to put a small panel between the meter and existing panel to do this.
/mike

Joined: Jul 2002
Posts: 8,443
Likes: 3
Trumpy Offline OP
Member
Hi Mike,
(LOL,sounds like I'm replying to myself!) [Linked Image]
Yes I agree, this probably going to be the only way that it can be done.
From what I gather, the switchboard panel isn't that spacious either.
I might get time to get some pictures tomorrow morning when I go to pull the pole fuse.
I'll keep you's posted.

Joined: Jul 2004
Posts: 200
U
Member
Yes, a contactor between the disconnect and the consumer unit would affect this request. As has been stated, a fuse would be required for the coils and associated gear for operating it, obviously on the 'maintained' side of the mains!

This is not unusual over here ( except in domestic properties! ). I have installed several shunts to shut off all except essential circuits overnight, or when unoccupied. Generally emergency and essentials ( like alarms/fridges/security lighting/emergency lighting ) would be on a maintained line; everything else down-wind of a sizeable contactor [Linked Image]

What's your guy gonna do for his fridge/s?


If hindsight were foresight, we'd all be millionaires!
Joined: May 2004
Posts: 186
A
Member
Sqare D and merlin make some nice little din rail mounted contactors that will go directly into a mains unit you could do all the internal wiring in the mains unit then. Contactors are about the same modular size as Mcb's (different widths for bigger contactors. Switch which ever contactors you like then. If he has the $ give him what he wants.

Joined: Aug 2001
Posts: 7,520
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Somebody has to ask: WHY? [Linked Image]

Joined: Jul 2004
Posts: 200
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Aland - without looking at the Merlin or []D cats, I can't see a suitably rated contactor fitting in there; they are rated at 80 -100A in line with the disconnect...

Paul, many commercial outfits, and such as churches/halls use non-essential shunts as added protection. You're guaranteed that everything is turned off, and that if someone enters/breaks into the building nothing will be switched/left on. It's generally buildings that are empty at night, or for longer periods. Some hotels/etc. also use them to be sure everything is turned off ( eg in the kitchen ) without having to go round and visual the whole place.

I guess a paranoid houseowner ( whos house maybe burned down previously through electrical fault ) might want to go that route... [Linked Image]


If hindsight were foresight, we'd all be millionaires!
Joined: Aug 2001
Posts: 7,520
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Sure, I'm aware of the benefits in certain applications. Although not remote-controlled with a contactor, I've generally set up my test bench with a master isolator switch; with so many different pieces of equipment plugged in, it's easy to miss something.

I just find it odd that somebody would want this in a normal house.

Joined: May 2004
Posts: 186
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UK, I will have a look in the catalogues when I get a moment am prety sure that yo can get contactors and timers and all-sorts of other gizzmos to go in the boards, seem to recollect contactors as low as 20 amps, ideal for lighting control if you like that sort of thing. I'm with you Paul Why? In the house!

Joined: Jul 2004
Posts: 200
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Yes Aland, you're right about the contactors you mention. But the original idea was to "isolate the house". Frame-mounts are available - I've used them - but I haven't seen rail-mounts that size...but then I haven't looked! [Linked Image]


If hindsight were foresight, we'd all be millionaires!
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