Extension cord experts - a question…

December 22, 2023, 01:54 PM

Skins2881

You've already got the answer. No.

If it was me, I'd measure the run, if it's under 250' buy a roll of 10-2 UF. Then add 20a rated male/female ends

This is still way undersized for 3% VD, but most equipment will run down to 110v. If it's purely resistive heat then you will just get lower heat output the lower voltage goes. I = V/R. The lower the V, the lower the I.

December 22, 2023, 03:01 PM

tsmccull

quote:
Originally posted by Sig Vicious:
300 feet is a long run and will cause a voltage drop at your load (heater). When voltage goes down, current goes up. The resistive load of the heater is less affected by this than an inductive (motor) load.

Using #14 cable gives a voltage drop of 20 volts. This could work for a resistive load but, as pointed out above, you will not get as much heating from it an the current will rise .

For a resistive heater load some of the info above is incorrect. I = E/R which means the current is determined by the voltage divided by the resistance. If the heater is a pure resistance (R), its value doesn’t change no matter what voltage is applied to it (as long as you’re not melting its wires or causing other physical damage). If the long extension cord (also acting like a low value resistor) causes the voltage (E) at the heater to be 20% less than it should be, then the current will also be 20% less (not more) than it should have been if there were no voltage drop. It’s ok to run the heater at the lower voltage value as long as the 20% lower amount of heat doesn’t cause a problem (insufficient heat to melt ice so the cows can get a drink, etc).

December 22, 2023, 04:01 PM

Jelly

Answer is No.

How big of stock tank are we talking about? How cold are we talking about. Sure a 500 W would not due?

December 22, 2023, 04:34 PM

4MUL8R

I like Jelly's suggestion. 500W would be a low cost temporary fix, and surely would keep the tank water from freezing. Less risk, less cost for the extension cord, and a safe alternative.

December 22, 2023, 04:43 PM

parabellum

I guess we do have extension cord experts here.

December 22, 2023, 05:08 PM

jed7s9b

Looks like the standard grade orange 12ga extension cords are the cheapest option. Three in series is about as far as I would use for 1500w.
Using 12/3 romex cable and installing plug ends on it would probably cost a little more but you get an honest 12ga wire. It also looks like 10/3 extension cords or romex more than doubles the cost.
I would decide which option will leave you the most useful leftovers when you get the issue fixed.

December 22, 2023, 05:17 PM

Blume9mm

I would for sure go with 12/3... but if it is temporary... why not just use Romex wire.

Now with that said, from my experience you are going to get a serious voltage drop... I suspect you'll be down to around 105 volts... this won't be a problem if the heater is just some basic resistive device with no solid state fancy new age stuff added.... other than a thermostat....

December 23, 2023, 10:17 AM

Sig Vicious

quote:
Originally posted by tsmccull:
quote:
Originally posted by Sig Vicious:
300 feet is a long run and will cause a voltage drop at your load (heater). When voltage goes down, current goes up. The resistive load of the heater is less affected by this than an inductive (motor) load.

Using #14 cable gives a voltage drop of 20 volts. This could work for a resistive load but, as pointed out above, you will not get as much heating from it an the current will rise .

For a resistive heater load some of the info above is incorrect. I = E/R which means the current is determined by the voltage divided by the resistance. If the heater is a pure resistance (R), its value doesn’t change no matter what voltage is applied to it (as long as you’re not melting its wires or causing other physical damage). If the long extension cord (also acting like a low value resistor) causes the voltage (E) at the heater to be 20% less than it should be, then the current will also be 20% less (not more) than it should have been if there were no voltage drop. It’s ok to run the heater at the lower voltage value as long as the 20% lower amount of heat doesn’t cause a problem (insufficient heat to melt ice so the cows can get a drink, etc).

You are correct.
I even though I knew that the load is resistive, I treated as though it were an inductive load.
I have edited my post to cause less confusion.

December 23, 2023, 10:30 AM

chellim1

quote:
Originally posted by parabellum:
I guess we do have extension cord experts here.

Definitely not me...
I tried running 4 sets of c9 Christmas lights through a dinky little extension cord and blew it out. With a heavier gauge extension cord I was able to get it all working, but I have no knowledge of the specifics.

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