How big of a wire gauge for a gate opener?

[4570Man]

Depends on the amperage, but ive run lots of openers at least 200 feet on #10 copper. If i were to run aluminum id run #6. There about the same price at the different gauges. Voltage drop doesnt even matter under 100’, then it starts to add up. If its only a battery charger it would not matter much. It does affect motor loads.

That’s what I suspected. I think I’ll go with 10 gauge copper.

 

[Grumpycat]

That痴 what I suspected. I think I値l go with 10 gauge copper.

I think you need more data. Nobody has said how much current is needed. Are we assuming 120VAC? 6awg copper for 200' 120VAC 3% voltage drop at full load for 60ï½°C maximum wire temperature in air.

There are two issues to consider: 1) how much current can the wire carry before it gets too hot? And 2) how far can you go before the voltage drop is deemed too great? At this distance the voltage drop will govern selection.

6/6/4 awg copper was about $4/foot before COVID insanity.

Better yet is 2/2/2 SEU aluminum. "SEU" is service entrance underground. Was $1.40/foot and good for 90A. For 120V @ 15A and 200' the voltage drop will be 1.2%.

"The thing is" they will need to make special effort to terminate the huge wires on each end. Probably need a transition from aluminum to copper. Really easy but freaks some people.

 

[chim]

That’s what I suspected. I think I’ll go with 10 gauge copper.

The key is the amperage, but your plan sounds solid for a load up to 12A. That puts you right at the NEC max branch circuit voltage drop of 3%. I didn't stay at a Holiday Express last night but I do hold a Harrisburg license I'd run a PVC pipe and fish it in.

 

[4570Man]

I figure a gate opener is probably 5 amps for a dinky one and maybe 10 for a better one but the customer doesn’t have the opener yet.

 

[chim]

Sounds OK to me then. Some of the same people who would recommend going to huge cable for that installation are happy plugging their 15A saw into a 14GA 100 foot cord that plugs into and outlet that is already 50 feet from the breaker that feeds it.

 

[Diggin It]

I have a low end Mighty Mule. Can't remember now if it's a 250 or 350. Operates a 15' gate I fabricated out of chain link fence rail. I ran whatever landscape wire had on hand, either 12 or 14AWG.. There are six 2W LED landscape lights on the same line. That terminates into the MM unit for the built in trickle charge for the battery. It's been working fine for close to ten years.

 

[Grumpycat]

The key is the amperage, but your plan sounds solid for a load up to 12A. That puts you right at the NEC max branch circuit voltage drop of 3%. I didn't stay at a Holiday Express last night but I do hold a Harrisburg license I'd run a PVC pipe and fish it in.

NEC's 3% voltage drop is so homeowner's don't complain about lights flickering. One would hope the opener's manual will specify a voltage range it will safely operate. Then you'll know how much you can let the voltage drop.

Still, 2/2/2 SEU is mighty cheap and rated for direct burial.

 

[dragoneggs]

Sounds OK to me then. Some of the same people who would recommend going to huge cable for that installation are happy plugging their 15A saw into a 14GA 100 foot cord that plugs into and outlet that is already 50 feet from the breaker that feeds it.

Exactly... 10g is overkill. 12g direct bury wire will be more than plenty for a 5amp and other stuff. You are not running a welder.

 

[4570Man]

Exactly... 10g is overkill. 12g direct bury wire will be more than plenty for a 5amp and other stuff. You are not running a welder.

Yes I thought 12 gauge would probably work and 10 gauge would be plenty and 6 gauge was ridiculous.

 

[dragoneggs]

Yes I thought 12 gauge would probably work and 10 gauge would be plenty and 6 gauge was ridiculous.

Another thing to keep in mind. A wire isn't going to get hot when it is used sporadically. The continuous draw just isn't there if I understand your application. Now if you are wanting to plug in some shop tools and build something... you would still probably be okay. . Just turn off the tool when the Mrs. comes home so you don't trip the breaker and she is stuck outside the gate!