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!)
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.
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.

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

Hi Mike,
(LOL,sounds like I'm replying to myself!)
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.

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

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

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.

Somebody has to ask: WHY?

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...

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.

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!

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!

Paul,
I must say I'm with you on that comment.
I'm just glad it's not my job to install this equipment.
uksparky,

On the surface of things, I don't really think that the home-owner has put a lot of thought into what effect this is going to have on his house.
When I was having a "walk-through" look at the place yesterday, I can see this job turning into a real can of worms.
There's all sorts of gear that's going to have to be segregated from any Contactor system:

• The house is fed with 3 phase 230V.
• The house has Under-floor heating all through it.
• The guy has 2 fridges and 2 Deep Freezers.
• There is a 9kW Air Conditioning Unit that has a mains-operated timer controlling it and the timer isn't on the switchboard.
• The guy want's his alarm clocks to stay on too!.
• The security lighting is on a seperate timer and that isn't on the board either.
• My colleague tells me that there is a security camera system that is fed from a plug circuit, that is required to be isolated at night, but the home-owner wants the cameras on 24/7.

Adding to all this, the house is what you would call a country house, in the true sense of the word, the switch-board looks so old, I reckon Captain Cook installed it and there is very little room left on it.
I told my mate to run as fast as he could!.

This does sound as though he really hasn't thought it through properly. If lots of devices have to stay powered, then what's the point of wanting a main remote isolator?

If he's concerned about not leaving certain appliances on overnight, how about an X-10 type control system with all devices set to a common code?


[This message has been edited by pauluk (edited 12-01-2004).]

Wise move.

There cometh a point where you have to say...ummm....no

Sorry I couldn't get any pics while I was there, my camera was flat and also I had a rather busy schedule that day.
But the switch-board was a real shocker, it was full of old MEM Switch-fuse units and the like, none of your DIN Rail mounting gear here.
The whole panel measured (roughly) 1600 wide x 800 high, it was HUGE! and it was packed with meters and fuses
I went and dropped the fuses before we opened the panel up and it was full of old TRS wire and heaps of TRS-TPS junctions behind the panel.
We closed it again quickly!.
I re-inserted the fuses and told my mate what I thought and left.
I had a cold shiver run down my back after that one!.

Sounds like complete rewire time to me!

Just a lil' update on this one.
The job never went ahead, after my mate and I were talking on the 'phone, the cost seemed to get higher and higher!.
We added all of the essentials up and a few "other things" thrown in, the guy didn't like the cost of it all.
Anyhow, I hate to see a bad job get worse and considering that I had little input into this job, you guys can't prove a thing!!.
Thanks a heap for your advice though guys, it means a lot!.