I need a 50' extension cord

[pconroy]

I stood in front of the wire racks at Home Depot today staring at 8/3 "rubberized" - which isn't stocked.


I can have 10/3 and 6/3. But 8 gauge is special order.


I've got a 10AWG extension cord out there now but I see a big voltage drop (117v -> 110v) when the AC fires up. It's a 20A dedicated circuit. The AC draws about 13a after the start up inrush.


That amount of drop is bugging me.
The online calculators tell me I should see 2% with a quality cord. I should lose a couple of volts. Not 6 or 7...


That led me into thinking "^%$#%-it, I'll build my own using quality 8AWG wire."

And that led me to Home Depot and NOT seeing any 8AWG.


Building my own - should I punt on that idea and just get the Camco 10AWG 50' for $90???


Is there some other reason I could be seeing that large of a voltage drop? Could my "good" cord really be cr*p???


Arrrrg...
thanks

[madmaxmutt]

While I generally think you are on the right track finding the most capable power cord possible, I really think you need a MicroAir Easystart for your A/C.

[RetiredOne]

I run mine on a 12 gauge, 50 foot cord on a 20 amp circuit. I see around a 4 volt drop or so while it's running. No problems.

I've got a 10AWG extension cord out there now but I see a big voltage drop (117v -> 110v) when the AC fires up.

Is that just on start surge, or after it fires up and is running for a few minutes?

Is there some other reason I could be seeing that large of a voltage drop? Could my "good" cord really be cr*p???

Anything else turned on in the rig? Possibly the converter trying to charge the batteries at full voltage? That will pull a lot.

Also, how far is the outlet you're plugging into from your main panel? Any chance of a voltage drop because of that distance too?

[Grumpy]

Originally Posted by pconroy

I stood in front of the wire racks at Home Depot today staring at 8/3 "rubberized" - which isn't stocked.


I can have 10/3 and 6/3. But 8 gauge is special order.

Find an Electrical Supply House, Graybar as an example.

[DrSmart]

I like your idea to make one with 8/3. Just wondering if you've measured resistance on the cord you have to see if one of the legs has a poor internal connection point at the plug? Measure end to end on the hot, then neutral.

[pconroy]

Originally Posted by RetiredOne

I run mine on a 12 gauge, 50 foot cord on a 20 amp circuit. I see around a 4 volt drop or so while it's running. No problems.


Is that just on start surge, or after it fires up and is running for a few minutes?


Anything else turned on in the rig? Possibly the converter trying to charge the batteries at full voltage? That will pull a lot.

Also, how far is the outlet you're plugging into from your main panel? Any chance of a voltage drop because of that distance too?

Great questions all - thank you.


I measure 117V at the RV and then watch it drop to 111V when the AC is running, long after the start up surge.


Nothing else on, batteries are topped off. Like I say, I've got a voltmeter plugged into an outlet in the RV and watch it go from 117 to 111.


It's a dedicated 20A outlet in my "shop/garage" with nothing else running in there.
I like the idea of measuring the resistance on the cord.

[RetiredOne]

Also, keep in mind, you could run a #4 extension cord, but it's not going to change what's feeding the outlet. If the outlet has 12 gauge (which is normal residential wiring) going to it (hopefully, not 14 gauge), you can run whatever extension cord you want, but you still get the voltage drop from the 12 gauge.

It would be like taking your 5/8 garden hose, and connecting a 2" fire house to it, and wondering why you're not getting a larger volume of water, with the 2" line.

What's the distance from your main circuit breaker panel to that outlet in your workshop?

[RetiredOne]

Originally Posted by pconroy

I measure 117V at the RV and then watch it drop to 111V when the AC is running, long after the start up surge.

How about trying this test. Take a voltage reading at the outlet in the shop before you start the A/C and after it starts, to see what drop you're having at the shop outlet. If it's the same amount as the RV reading, then it's not the extension cord. Would be a good comparison.

Remember, besides the distance to the shop outlet from the panel, you're adding 50 ft of extension, then another 30 feet of the RV power cord.