Community Forums

ottffss · 12-02-2011, 04:24 PM

Quote:

Originally Posted by Wayne M

I read that 8AWG is rated at 73 amps,..

That would be for a single, unjacketed conductor in open air. It is NOT for multiple conductors that are jacketed (like in a cord).

AWG and ampacity is NOT a simple subject.

Mr_D · 12-02-2011, 04:30 PM

Quote:

Originally Posted by ottffss

That would be for a single, unjacketed conductor in open air. It is NOT for multiple conductors that are jacketed (like in a cord).

AWG and ampacity is NOT a simple subject.

Isn't that the truth!!

Somewhere I think I still have my electrical theory book from college! And that was 40 years ago! Probably should throw it out by now though.

Luv2go · 12-02-2011, 04:32 PM

Quote:

Originally Posted by Mr_D

Isn't that the truth!!

Somewhere I think I still have my electrical theory book from college! And that was 40 years ago! Probably should throw it out by now though.

Don't! I suspect the info is just as valid today as it was 40 years ago!

ottffss · 12-02-2011, 04:40 PM

Quote:

Originally Posted by Mr_D

Somewhere I think I still have my electrical theory book from college! And that was 40 years ago! Probably should throw it out by now though.

Keep the book!!!! Electricity has not changed in the past 40 years - unless a new world order has set in. That book is still completely valid!!! NEC and other codes might have changed but not the physics!!

Elkhartjim · 12-02-2011, 04:46 PM

Mechanical engineer here so I'm going to look for that Holiday Inn Express Route 66 slept in and let you EE's figger this'n out.

She and I · 12-02-2011, 04:53 PM

Quote:

Originally Posted by Wayne M

I read that 8AWG is rated at 73 amps, where 6awg is rated at 101 amps. That would be for each section of a 4 pair wire.

Hey Wayne, You are correct except 6AWG with proper coating is preferred,
If you have wire with a 75C or higher rating, and if all of the terminals that the wire connects have a 75C or higher rating, and if you are not using NM or UF cable (which are specifically restricted to use at 60C ampacity), then yes, 8ga conductors are suitable for 50A. But not likely

Copper wire, not Aluminium.

Richard

wardy · 12-02-2011, 04:57 PM

Quote:

Originally Posted by ottffss

That would be for a single, unjacketed conductor in open air. It is NOT for multiple conductors that are jacketed (like in a cord).

AWG and ampacity is NOT a simple subject.

How true! First you learn DC which is pretty simple to grasp and favored by Edison. Then you learn AC (favored by Tesla) and it behaves much much different. I think we're caught in that here a bit. If you look up ampacities you may see an amp figure that was quoted for DC that is steady rate. But that same cable will have a lower AC rating due to varying current/voltage and since AC is rated less than peak wave (RMS)......

Paul R. Haller · 12-02-2011, 05:06 PM

Any large cable supplier will carry SO (soft copper very flexible with an oil resistant outer coating) 4 conductor 6 gauge wire cable but that isn't really what you want. It will work but the cables used for RV applications have a very heavy vinyl jacket to prevent abrasion and the ends are molded to prevent water and contamination into the plugs. I have built specialty cables before but the cable is expensive and the ends are also but these cables I made were for a Remote Computer Cluster that cost 350,000$. You would be hard pressed to buy the parts and make it for less then the ones on ebay that are made en mass in China. Another option is to scavenge one from a wrecked motor home or large 5er and just put one end on it.
-Paul R. Haller-

Paul R. Haller · 12-02-2011, 05:12 PM

look here: Camco 55194 50 Amp 15' RV Power Grip Extension Cord | eBay

ottffss · 12-02-2011, 05:40 PM

Quote:

Originally Posted by Paul R. Haller

look here: Camco 55194 50 Amp 15' RV Power Grip Extension Cord | eBay

Same cable is a lot cheaper on Amazon as linked way above (first page)....

Happycarz · 12-02-2011, 08:41 PM

So what's the matter with the Camco from Amazon.com? The Product Features states it has (3) 6 gauge wires and (1) 8 gauge wire.

HHIDan · 12-02-2011, 08:59 PM

Quote:

Originally Posted by wardy

I made one and use it at my home. I ordered 100 feet 6-4 stranded from Lowes. Then tied in a clothes dryer plug and outlet. It works perfect.

I made one (a 60 footer) with the same wire but I used "stove" plugs female connector in a metal box at one end and a 6 foot male cord at the other end. Not as pretty as the real RV type but cheap as I had most of the parts.

Arch Hoagland · 12-02-2011, 09:35 PM

I looked into making my own and found that there wasn't enough difference in price to make it worthwhile.
If you do make your own make sure you tighten the screws REALLY good. If those screws loosen heat will develop at that point and melt the connector.
A molded premade cable usually doesn't have that problem because the connectors are crimped on and that was part of my decision to buy a premade.
I'm glad I have a longer cord because there have been a couple times I really needed it.

Wayne M · 12-02-2011, 09:59 PM

Richard,
The chart shows 40A and 7680Watts for 240 volts, but the calculations I come up with for 7680W at 240 Volts is 32A. However, I don't run 240 volts, I run 120 volts on two legs and each leg is capable of 50A at the breaker. So at 120 volts, 7680W I could handle 64 amps, but the breaker should trip if one leg goes beyond that. Or my PT50-C kicks in.

I'm with Jim. I'll let all the EE's handle this one. I have what I have, I have used it, and it works. I am glad I had it with me. So to the OP, having an extension cord is like having an extension for your sewer hose. You don't need it until you need it.