I bought the electrical box with my DC. The inference from the instructions is that you want separate 230V and 115V circuits. But I wonder if I can just bleed off some 115V from one leg of the 230V connection. It looks like all the 115V is used for is for the remote, and I can't believe any real amperage at all is drawn for this. I figure I can just run 2 hots, and neutral, and a ground. Thoughts?
Power to electical box
- Thread starter wavery
- Start date
If you go that route, NEC requires a four conductor feed on the 240 line (2 hot, a neutral and ground) if separate loads are used on each hot leg (that is why newer model electric clothes dryers have 4-prong plugs on them). The CV Electrical box come pre-configured with a 120 V cord ready to plug into a standard 15-amp outlet for power to the remote unit and contactor coil, so why rewire what you've already paid for. Your cost for the 240 wire will be higher (10/2 versus 10/3 NM cable). In my experience with my Bin Sensor power supplies, having them on a circuit with a motor can cause electronics failures and your proposal may impact the electronics in the remote control outlet pre-configured with the electrical box. The cause of failures is a voltage drop on the 120 leg when the CV blower motor comes on and draws heavily to get the impeller up to speed. That configuration may cause the electrical box remote to fail. I'd recommend you use a separate 120 V outlet with the Electrical Box as designed. If you decided to purchase one of the Bin Sensors from CV (which I supply), I cannot warrant it with the 120 volt power on the motor power leg.
There would be other complications as well. The motors 240v breakers are likely 30 or 40A. You would need to provide separate over current protection for the 120v circuit. Adding this within the Clearvue box would void its UL listing. At that point you would be fully assuming liability and responsibility for the design.
Whatever you do, don't let the magic smoke escape!!
Whatever you do, don't let the magic smoke escape!!
Power to electrical box
Power to electrical box
thanks for the advice. My thought process was that I'm installing the DC behind my shop and there will be a hassle factor to installing the 240V circuit, so was trying to avoid running an additional 115 circuit as well.
I appreciate the prompt replies.
BTW, a nit on McRabbet's response - you really want to run #8 wire, not #10
Power to electrical box
thanks for the advice. My thought process was that I'm installing the DC behind my shop and there will be a hassle factor to installing the 240V circuit, so was trying to avoid running an additional 115 circuit as well.
I appreciate the prompt replies.
BTW, a nit on McRabbet's response - you really want to run #8 wire, not #10
There would be nothing wrong with running #8 or #6, or even larger although #10 is acceptable because the FLA of the motor does not exceed 30 amps. The NEC has an exemption for motors that permits the breaker to be sized larger than the wire size, if required to handle the inrush current for the motor, as long as the motor contains internal thermal protection. The code says the breaker should be as small as possible however you can take the FLA @ 225% and then round up to the next standard breaker size. If the motor's FLA was 24A it could, by code, use a breaker up to (225% of 24 = 54, rounded up to) 60A.
I once dug pretty deep into this topic after I purchased a "5hp" Delta Unisaw and noted its plug was a 6-20p (20 amp rated) using 12 gauge wire. The mating receptacle (6-20r) will only accomodate up to 10ga wire. The FLA rating of the motor is 20A yet they tell you to install a 40A breaker. After reading the above in the NEC I talked with a number of fellow Electrical Engineers to confirm what I was reading and even discussed it with UL (who lists the device) and my local inspector. All confirmed this is true.
Now, this is for a receptacle dedicated to this use and should not be used by an electric heater, lighting or other devices. As a safety precaution I labeled the receptacle cover.
Jim in Alaska