350 ft 240v 15 amp circuit/ least expensive way possible.

[techniphase]

any body ever step up awg every 100 ft at 300 ft to save money? would it work?. 14awg to j box then 12 awg to j box to 10 awg for xray machine w power conditioner. ( x ray machine min v is 225 , max 231 volts single phase ( also looking at using 6 awg aluminum for the entire run and driving ground rod at machine to save money) anybody?

 

[templdl]

Have you considered using a step-up transformer from 240-480 then step-down from 480-240? That way you would be cutting the current in half and able to use a smaller wire size.
You would have to compare that cost against the cost of larger cable to combate voltage loss.
Driving ground rods at the machines? If I read your post correctly your intent of using ground rods is to save of the cost of running a grounding conductor.
Where would these ground rods come into play other that regrounding the grounding conductor.

 

[infinity]

So your supply is 240 volts but the machine is rated for a maximum voltage of 231 volts? For a 15 amp circuit the EGC would need to be the same size as the ungrounded conductors even if they're increased for voltage drop.

 

[iwire]

any body ever step up awg every 100 ft at 300 ft to save money? would it work?. 14awg to j box then 12 awg to j box to 10 awg for xray machine w power conditioner.

OK, it seems you are trying to apply a loose rule of thumb incorrectly. Your circuit is 15 amps so it would normally use 14 AWG, but the length is 350 so using this rule of thumb you would increase 3 sizes

You would run 8 AWG copper for the entire run.

Now voltage drop is dependent on the current, you have not given the current, you gave us the circuit size. That being the case I will say the actual load is 12 amps.

• At 12 amps a 350' long circuit on 8 AWG will have approximately 2.7% voltage drop
• At 12 amps a 350' long circuit on 10 AWG will have approximately 4.2%% voltage drop (Too much in my opinion)
• At 12 amps a 350' long circuit on 12 AWG will have approximately 6.7% voltage drop

( x ray machine min v is 225 , max 231 volts single phase

Is the power conditioner rated to drop 240 down to 230?

( also looking at using 6 awg aluminum for the entire run and driving ground rod at machine to save money) anybody?

This one scares me, there is no code compliant way you can save money on this circuit by adding a ground rod.

If you are suggesting eliminating the equipment grounding conductor that is perhaps the worst idea you could come up with. Where is this machine loacated? it might even require redundent equipment grounding.

 

[ptonsparky]

Cut your labor rate. Material costs are minor in comparison and could result in a less than satisfactory result.

 

[kwired]

Is this X-ray equipment medical equipment or other?

Either way it is likely somewhat expensive equipment to start with, now they want to cut corners with installation. Not running proper supply could cause more damage than what will be saved, will likely void warranties and so forth. I would offer to do it right or get somebody else. When something does fail they can come back to you and say you did not install it properly. Then you will wish you never did the job.

 

[augie47]

............................................... and driving ground rod at machine to save money) anybody?

Please tell us you don't propose this instead of an equipment grounding conductor........ !!!

 

[kwired]

Please tell us you don't propose this instead of an equipment grounding conductor........ !!!

I don't know why I did not mention anything about this in my previous post, it is one of the areas I usually never fail to mention something if I see it.

Hope OP has good insurance.


If this is not medical X-ray equipment and he uses a metal raceway he may not need a separate EGC unless the equipment would specify the need for it anyway.

The cost difference between 350 feet of 14 AWG vs 350 feet of 8 AWG has to look like pocket change compared to cost of the X-ray equipment I would think.

 

[iwire]

If this is not medical X-ray equipment and he uses a metal raceway he may not need a separate EGC unless the equipment would specify the need for it anyway.

I did not get the impression there would be a raceway, he mentioned SE as an option.

 

[kwired]

I don't see any SE mentioned as an option. He wouldn't have the potential EGC issue with SE unless he also needed a neutral and was not using SER.

His original idea of stepping conductor sizes has some validity but you would want the larger conductors near the source and the smaller conductors near the load. Still 14 AWG vs 10 or even 8 is not really that much cost difference. They can both possibly fit in 1/2 inch raceway so that cost is same, extra splice boxes and time to set up, pull and terminate each different size may still be more than going same size all the way with little or no splice/pull boxes if you can do so.

 

[iwire]

I don't see any SE mentioned as an option.

Sorry you are right, when I read aluminum I assume SE / SER

He wouldn't have the potential EGC issue with SE unless he also needed a neutral and was not using SER.

Actually he could still have an issue due to downsized bare conductors in SE / SER

His original idea of stepping conductor sizes has some validity but you would want the larger conductors near the source and the smaller conductors near the load

I would love to see the math that proves that to be true with just one load.

In either direction it would result in too much VD.

Still 14 AWG vs 10 or even 8 is not really that much cost difference. They can both possibly fit in 1/2 inch raceway so that cost is same, extra splice boxes and time to set up, pull and terminate each different size may still be more than going same size all the way with little or no splice/pull boxes if you can do so.

I want to see you fit two 8s in 1/2" hmy:

 

[kwired]

Sorry you are right, when I read aluminum I assume SE / SER



Actually he could still have an issue due to downsized bare conductors in SE / SER



I would love to see the math that proves that to be true with just one load.

In either direction it would result in too much VD.




I want to see you fit two 8s in 1/2" hmy:

I've pulled 3 - 8's in 1/2" a few times, but would not even try to do so on a 350' run. Probably would not try to do so on a 50' run, unless raceway was already available to pull through. New run is getting at least 3/4.

 

[iwire]

I've pulled 3 - 8's in 1/2" a few times,

I would not even contemplate doing it. :happyno:

 

[bob]

I would love to see the math that proves that to be true with just one load

When the distances are all the same, as in this pproblem 100 ft, it does not matter.

If the distances are different, eg, 100, 75, 50, it matters that the larger conductor is in the first run.

 

[kwired]

I would not even contemplate doing it. :happyno:

You wouldn't pull them through 2 inch either, you would have your help do it:happyyes:

 

[techniphase]

The ground rod would create my ground at the power conditioner( saving the ground wire run 350 ft from source) , it is a merchandise x ray machine in warehouse, the power conditioner will create the proper voltage fluctuations the machine requires. the machine comes with an SO cord that will plug in to the outlet on conditioner. Like you guys are saying, i realize the cost of the xray machine is far greater than any risk on cheapo on the wire. very good replies from all of you, i think ill stay with my original idea, RUN THE DAM WIRE RIGHT! lol. #8 straight through. happy trails,

 

[techniphase]

using 1" emt, thought maybe 3 #6 aluminum, 350 ft , 240v w N. from source, getting ground at other end w new ground rod. every 100 ft pull boxes, after pricing it, not much more to run #8 cu.

 

[Ponchik]

The ground rod would create my ground at the power conditioner( saving the ground wire run 350 ft from source) , it is a merchandise x ray machine in warehouse, the power conditioner will create the proper voltage fluctuations the machine requires. the machine comes with an SO cord that will plug in to the outlet on conditioner. Like you guys are saying, i realize the cost of the xray machine is far greater than any risk on cheapo on the wire. very good replies from all of you, i think ill stay with my original idea, RUN THE DAM WIRE RIGHT! lol. #8 straight through. happy trails,

You need to install the EGC unless your conduit is metallic. What you are proposing with the ground rod is dangerous.

you don't need a pull box every 100' either.

 

[iwire]

The ground rod would create my ground at the power conditioner( saving the ground wire run 350 ft from source)

This is, false, unsafe and a direct code violation.

250.4 General Requirements for Grounding and Bonding.

(5) Effective Ground-Fault Current Path.

Electrical equipment and wiring and other electrically conductive material likely to become energized shall be installed in a manner that creates a low-impedance circuit facilitating the operation of the overcurrent device or ground detector for high-impedance grounded systems. It shall be capable of safely carrying the maximum ground-fault current likely to be imposed on it from any point on the wiring system where a ground fault may occur to the electrical supply source. The earth shall not be considered as an effective ground-fault current path.

 

[ptonsparky]

This is, false, unsafe and a direct code violation.

Hint: Others have been alluding to this since post 2. You must have an EG and the earth does not qualify. Two choices. Metalic raceway or a green wire, all the way.