I was just thinking that given the small load it may not be worth the expense and hassle of using a transformer at the supply end. But your right, a little cost analysis is in order.
That's kind of what I was thinking I did the numbers at 7 amps I came up with 8awg. I installed an outlet for a comparable gate opener today it pulled less than 1 amp.
Use Ohm's Law to figure out how low a resistance must be to make sure, say, 20 amps will flow on 120v.
.To shaded for solar. I know what you mean I'll have to deal the the electric leaf blower being plugged in every year.Since I'm doing wild ideas at the moment- A small solar setup. Inverter to make AC for the gate, batteries to store, panels to charge, loooonnngggg run of AC for backup and a small charge current.
Nah, way too complicated.
A lot depends on the gate motor voltage & starting current. Add a side note that the moment someone sees 120v power out there, they're going to want to connect something else (small fountain, de-icer, more lights, security camera, etc).
Could you show me an example of how to do this properly?
I don't think its quite that simple. using E/I=R 120/20 = 6 ohms. Dividing 6 by the resistance of #12 awg will give you the total feet one way. That is the worst case and while 20 amp will flow, its not enough to trip a 20 amp CB. You would need to look at time current curves of the CB or fuse to determine when you are happy with the time it takes to opening the circuit. Reducing the length of the wire or increasing the size will give the results you want.
Seems like a lot. Just a thought out of curiosity if you kept the circuits voltage drop within the 3 percent recommended range should it typically have low enough impedance to properly open the OCPD in a fault.
Question. For available fault current should I put infinite bus....... or if I had a series rated panel with a main breaker with a 22kiac rating would that be my available fault current?
I’m cheating on this. I’m not Looking to see if the breakers can handle the maximum fault. I want to know if the the fault current is enough to operate the fuse or breaker. I would use what you think is actually available. Use the results of your first calc for The start of the second, etc. Work all the way from the poco transformer down through the feeders to the end of the branch circuit. I worked this for some pivots last year and found it was going to take 15 or more seconds to blow 30 amp fuses for the wires I used. Not good in my opinion.
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