ECN Forum Forums General Topics of the Trade General Discussion Area 2 loads sharing 1 breaker.

Estimated a job installing a car lift. The panel is full but I could tie into the balancer machine in a junction box feeding it. It is the right size circuit too. The manager said they would never use both at the same time. Is this legal?

In Canada, I think it is allowed if you install a transfer switch, so only one unit can be used at a time.
Is it easier to put in a sub-panel to create breaker space?

Another solution is to install one receptacle and put a cord end on each unit. They would only be able to connect one at a time.
They may 'promise' not to use both at once, but make sure they are incapable; otherwise they may just put in a bigger breaker after you leave.

Is the new unit a long way from the panel?

aldav53,
What sort of current are we talking here, between the 2 loads?.
What size/type breaker protects these 2 circuits?.
Normally there shouldn't be a problem, unless the breaker trips and the car-lift loses pressure.
Is there any way that you can install a Sub-Panel, from the Main Panel?.

To start with, you will need to meet the requirements in section 210.23

You really have not given enough info to determine if the installation is legal. I suspect it is not, if you are worried about them using both pieces of equipment on the same circuit.

What about a "mini" breaker? If a mini will work you should install a separate neutral.

It is a 20 amp 208 volt 2 pole circuit. They don't make a mini breaker for a bolt in type. If the breaker tripped the hoist would not lose pressure. The panel is a fair distance away and so is the hoist from the balancer. If they did run them at the same time the circuit would probably hold it, (I will check the amp draw on the balancer).
I don't think there would be a problem, as long as it is code compliant.

Ok, more information is good.
If you intend to feed both pieces of equipment from the 20a breaker then your combined load will be the key. You should be able to find the amps on the nameplates of the equipment in question.

I would not install both pieces of equipment on the same circuit if their combined load exceeds the load allowed, by the NEC. It is legal to install multiple pieces of equipment on a given circuit, but the installation must meet the requirements of the NEC. The managers word about equipment useage - is not an exception to the NEC or a disclaimer for possible injury to people and damage to property.

I had recently done a lift. It was the kind that the car was elevated off the ground by a cable/ hydraulic unit. It wasn't the old big tube in the ground type. The lift had a contactor (3 phase) and we needed to have a circuit ran to it. I would reconmend a line by itself, just for the lift. There is a lot of weight involved and a guy stands under the car to work. Why take a chance?

Those old ones work on air pressure I believe. This new one uses an electric motor to raise and lower, so if power is off it won't go down.

"There is a lot of weight involved and a guy stands under the car to work. Why take a chance?"

Chance of what??? All lifts have safety cams to prevent them dropping and this has nothing to do with the electrics.

Do exactly as Wireman said, if the combined load is within the 80% of the breaker's rating. This could be considered a non-continuous load since a tire balancer or lift theoretically could never be used for 3 hours straight. I would still stay under the actual rating of the breaker.

Speedy,
That makes good sense.