Wire Size for 30 amp 230 v

[kool55]

I am running a 230 volt 30 amp circuit to a Horse Walker from my Barn. The run is 250 ft. Going to run off a 30 amp breaker in the barn to a disconnect switch outside the barn, then in conduit underground to the Walker Control panel.
4 wires-2 hots, N and grd.
What AWG should I use and does the grd. need to be the same?
Also , can I tap off one of the hot legs to operate a 30 amp 120 v RV hook up
half way down the run ? thanks

 

[alfredeneuman]

It will depend on the load of the hot walker.
Look at the nameplates on the machine, controls, and motor as to how many amps, horsepower, etc.

 

[pattenp]

Because of being 250ft to handle up to the full 30A if needed, you need #4 Aluminum or #6 Copper. I'd go with the aluminum simply because of cost. You can add the RV hook up but you need to take into account the total possible load on the circuit. You should size the circuit at 125% of the total anticipated load.

 

[nelstomlinson]

Per code, a 30A breaker can feed nothing smaller than 10 gauge. I would certainly make the ground the same size.

Voltage drop matters. A 30A breaker can feed a continuous load of 0.8(30)=24Amps, so that's your maximum amperage (we will ignore motor starting surges). V=IR, and from memory, for the 500 foot round trip, R will be about 0.5 Ohms. That's a 12 Volt drop, which is 12/240(100)=5% drop. That's a little high, so if you will have anywhere near a full load on that circuit, I would advise going up to 8 gauge wire, or even larger. Definitely up-size the ground to match.

You can certainly feed a 30A 120V outlet along the way, but the amps from that are going to add to the load, and you could wind up tripping that 30A breaker if you try to use both the center and end loads at the same time. Again, don't use anything smaller than 10 gauge.

 

[nelstomlinson]

Because of being 250ft to handle up to the full 30A if needed, you need #4 Aluminum or #6 Copper. I'd go with the aluminum simply because of cost. You can add the RV hook up but you need to take into account the total possible load on the circuit. You should size the circuit at 125% of the total anticipated load.

Pattenp, does code let you put a 30A outlet on a larger-than-30A circuit? I recall that's a no-no for 15A and 20A outlets.

 

[sberry]

Use number 2 aluminum to a 6 space panel. That will give solid 50 or 60A service, can wire an outlet from there and the wire is about as cheap as it can get done.

 

[nelstomlinson]

Sberry, that's good advice.

One thing we haven't talked about is what <i>kind </i>of wire and conduit. That conduit will fill up with water, so use XHHW or THWN. I'd use HDPE or PVC underground.

 

[sberry]

Depending on ground,,,, it is rated direct bury. I have 1000's of feet in direct, never a problem. POCO does it all the time.

 

[kool55]

The Walker requires a 30 amp 230v circuit. They don't specify wire gage because of unknown
distance. I did one of those online calc formulas and came up with 6 AGW. Thought about 4 AGW because I couldn't figure the Walker acceptable voltage drop. Was going to run the wire thru 1- 1/2 pvc.
I ask about tapping off this circuit for the 120v 30 amp. circuit because it would save me 90 feet of wire. With this configuration I only need about 15 feet to the RV box. Would not run both circuits at the same time so I can stay with a 30 amp breaker

 

[kool55]

Was looking at THHN wire.

 

[Norcal]

Was looking at THHN wire.

Unless the THHN is dual rated as THWN it cannot be used outdoors or under ground.

 

[pattenp]

Pattenp, does code let you put a 30A outlet on a larger-than-30A circuit? I recall that's a no-no for 15A and 20A outlets.

For general use you are not to put a 30A outlet on a circuit larger than 30A. But you can use duplex 15A outlets on a 20A circuit, but a single dedicated 15A outlet is to be on a circuit no larger than 15A. Outlets for welders are an exception.

 

[theoldwizard1]

Also , can I tap off one of the hot legs to operate a 30 amp 120 v RV hook up half way down the run ?

Install a sub panel Where the RV hook up is going to be. Put the RV plug on one breaker and the hot walker on the other.

Small panels typically do not have a "main" breaker. Add a third breaker and just use it as you main. This way, it the combined load exceeds the load of the breaker in the barn it will (hopefully) trip at this sub panel.

 

[wyliesdiesels]

Depending on ground,,,, it is rated direct bury. I have 1000's of feet in direct, never a problem. POCO does it all the time.

Which wire types are you saying are direct burial rated?

And direct bury ratings are based on insulation type not ground type.

Maybe youre trying to say something else here...

 

[sberry]

Dirt,, the soil it's buried in .

 

[wyliesdiesels]

Didnt answer my question but whatever..

 

[kool55]

A lot of good info here. Thanks guys. A sub panel sounds good but with all the horse stalls, the only location for one is right next to the sliding door. Too close to the outside weather for code? All my runs are above the stalls.At the main panel ,is there a breaker that can take #2 wire ?
THHN wire is not ok underground in pvc conduit? I read that most all THHN is dual rated today but the site was checking pricing did not mention that.

 

[sberry]

Use an outdoor panel, mount it on the outside.

Didnt answer my question but whatever..

You don't know?

 

[kool55]

Found a RV hookup panel from Connecticut Electric that has a couple of breakers in it.
I can use it as the tap off to continue the 230v 30 amp line to the walker. Run the feeder wire to it from the main panel. Cleaner and cheaper. I post a pic of it when I can.

 

[kool55]

This the RV panel that I can use as a sub to continue the 30 amp 230v line to the Walker. Should make for a cleaner install.

 

[nelstomlinson]

A sub panel sounds good but with all the horse stalls, the only location for one is right next to the sliding door. Too close to the outside weather for code?

Use a NEMA 3R panel and you can mount it outside, if you want. If there are fewer than 6 handles in it, you don't need a main breaker or disconnect.

 

[wyliesdiesels]

Use an outdoor panel, mount it on the outside.
You don't know?

Dont know what?

 

[sberry]

I was being a smart azz,, disregard it.

 

[kool55]

Got the RV panel and found out the breakers are for the 30 and 50 receptacles.
So I will feed this from a junction box inside above the horse stall using a 3 terminal insulated bug. Need one each for the GRD. ,N , and one hot leg since the RV hookup is 120v.

 

[sberry]

What is the RV panel? By using a common 6 space panel you don't need another junction box and can add breakers for circuits. You could have both voltages and 20A /120

 

[kool55]

This the RV panel that I can use as a sub to continue the 30 amp 230v line to the Walker. Should make for a cleaner install.

The RV panel has a receptacle for plugging in a power cord for a Motorhome or
a LQ Trailer without using the onboard generator. The one I have has bot the common 30 amp recep. and a 50 amp. recep. along with a duplex recep.
I initially thought there was an available breaker in it that I could use to split up the 270 ft run.

 

[kool55]

OK,another question about disconnect switches. I am installing a Siemens 2 pole 230v. 60 amp. D/SW. That takes care of L 1 and L2.
To be approved for a service disconnect sw. ,do I need a 3 pole so I can disconnect the Neutral. I will add its non fused , and the Walker motor is 30 amp 3 hp. single ph. Thanks

 

[kool55]

I forgot to mention the reason for the D/SW. is to be able to quickly shut down the Walker from the Barn if something goes wrong rather than running 120 ft. to the shut down button on the control panel at the Walker.

 

[nelstomlinson]

OK,another question about disconnect switches. I am installing a Siemens 2 pole 230v. 60 amp. D/SW. That takes care of L 1 and L2.
To be approved for a service disconnect sw. ,do I need a 3 pole so I can disconnect the Neutral. I will add its non fused , and the Walker motor is 30 amp 3 hp. single ph. Thanks

I don't know what your AHJ is going to want to see, but I wouldn't spec a three pole switch, and wouldn't want to disconnect the neutral. Also, if this is a service entrance, this is where you bond the neutral to the grounding electrode, right?