How many extension cords are safe?

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winona

winona

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I'll need to move my Trend to the end of the driveway and keep it there for a month -- new concrete.  I already use a 25 - 30 foot 30 amp extension cord plugged into the power cord (probably another 25 feet long) to keep it plugged into the outlet in my garage.  Is it safe to add another cord?  Is there a maximum length of cords?  All I need is just to get the fridge ready and run the ac before a trip.
 
It's not the number of cords you use, but the overall length and the AWG (gauge) rating of each. The longer the length, the lower the AWG you need. The AWG is on the cord and packaging.

I just bought a 75 foot and 25 foot outdoor extension cords from Harbor Freight Tools that are both 14 gauge/AWG. I use these so my shop vac can reach my car from my apartment. Not sure if it same, but they sell the same overall length (100') cords in the same 14 AWG, so I assume it is safe. They also sell 12 gauge in the same length, but those cost more money.

Can someone else here chime in?
 
There are numerous charts available on line that will spell out the required cable size for a given distance and current draw.
 
The more extension cords you use, the greater the voltage drop.  On a hot day, when everybody and their kid brother is trying to run their air conditioners, the whole grid may be very low, in which case a long run of extension cords may put your voltage at the RV into the brown-out range, which could very possibly damage your RV's air conditioner if you try to run it.
 
winona said:
I'll need to move my Trend to the end of the driveway and keep it there for a month -- new concrete.  I already use a 25 - 30 foot 30 amp extension cord plugged into the power cord (probably another 25 feet long) to keep it plugged into the outlet in my garage.  Is it safe to add another cord?  Is there a maximum length of cords?  All I need is just to get the fridge ready and run the ac before a trip.
Click to expand...
Why not use your generator to run the A/C before a trip? That way your lengthy extension cord(s) will be less likely to cause a problem.
 
If you are plugging into a 15A outlet at the house, then no problem becasue even 3x 30A (75-80 ft) cords can carry 15A that far.  However, 15A is skimpy for running fridge and a/c.  Have you done this already at home?  Some rigs can manage it ok, while others tend to trip breakers.

If you have a 30A outlet at home, then more than 50 ft of cord is pushing things. Human nature is to use more power when more is available, and trying to get 25 or so amps through a 75-80 feet of cord can cause voltage drop (bad the appliances) and overheated wires (especially where those cords plug togther or at the house end).
 
Problem sort of solved.  I'll take up the neighbors on using their yard and just start the fridge on propane when I need to.  The generator would be too noisy, and I like keeping all my neighbors happy.  :)  My outlet in my garage is 20 amp and so far, no problem.  And I'm sure that just jinxed that, huh.  :eek:
 
winona said:
Problem sort of solved.  I'll take up the neighbors on using their yard and just start the fridge on propane when I need to.  The generator would be too noisy, and I like keeping all my neighbors happy.  :)  My outlet in my garage is 20 amp and so far, no problem.  And I'm sure that just jinxed that, huh.  :eek:
Click to expand...
No problem if you are close enough but the longer the run with smaller gauge wiring the higher the resistance to flow. This would require more wattage. Increased wattage could put you over the 20 amp. Specially on A/C startup. Now if you had a hard start capacitor on the A/C we might talk again
 
Invest in the 12 guage extension cord.  The little extra it costs is more that offset by it's better ability to maintain the voltage.  FWIW we always carried 2 50 foot 12 guage extension cords, and only rarely used them together, and if required, we were careful as to what electricity was used, but don't forget the draw of the charger to maintain the batteries. 

Ed
 
First. What all are you trying to RUN?

Fridge draws less than 4 amps so if you were to use say a 100' 12ga Extension cord (as I do on occasion) you'd plug it in turn off EVERYTHING in terms of electrnoics A/C, Fridge, Water heater. let it sit 2-4 hours (Giving the batteries time to charge) and then kick on the fridge.. Should be good. Just don't try an A/C on that hook up.  Or heat water.
 
John From Detroit said:
First. What all are you trying to RUN?

Fridge draws less than 4 amps so if you were to use say a 100' 12ga Extension cord (as I do on occasion) you'd plug it in turn off EVERYTHING in terms of electrnoics A/C, Fridge, Water heater. let it sit 2-4 hours (Giving the batteries time to charge) and then kick on the fridge.. Should be good. Just don't try an A/C on that hook up.  Or heat water.
Click to expand...

OP stated she wanted to run the A/C
 
I see no problem with 3x 30A shore cords + extensions going to a 20A outlet.  A 12 gauge cord will carry 20A OK for 25 ft or so, but 75 feet of 12 gauge is probably going to come up short. 
 
Don't forget to consider the length of the wiring between the circuit breaker box and the outlet you're plugging into.

A 20 amp circuit usually uses 12 gauge wire, a 15 amp circuit usually has 14 gauge wire connecting the outlet to the breaker box. 

If the breaker box is some distance away, you may have 25 -50 ft. or more of wiring between the box and the outlet, which will drop just as much voltage under load as adding the same length of extension cords between the outlet and the RV.
 
"How many Extension Cords Are Safe"?

I would assume most of them unless they are frayed.
 
KandT said:
"How many Extension Cords Are Safe"?

I would assume most of them unless they are frayed.
Click to expand...

And that would be an incorrect assumption. Many fires have started and equipment damaged with that assumption.
 
winona said:
I'll need to move my Trend to the end of the driveway and keep it there for a month -- new concrete.  I already use a 25 - 30 foot 30 amp extension cord plugged into the power cord (probably another 25 feet long) to keep it plugged into the outlet in my garage.  Is it safe to add another cord?  Is there a maximum length of cords?  All I need is just to get the fridge ready and run the ac before a trip.
Click to expand...

10 gauge is recomended for any run of 120v 15 amp from 65' to 100' from the breaker box not the outlet. 40-65' use 12 gauge. Anything shorter can use 14 gauge. Go up one gauge larger (ie 8 instead of 10) for 20 amp. Always use the correct wire size whether you plan on using all the available amperage or not, that way if there is a short the breaker will trip before the wire melts and catches on fire. Also keep in mind that the outlets were wired for the distance from the breaker box to the outlet and no further. Really long runs will tax the wiring in the wall if you only use large gauge wire from the outlet to the rv. It is never as simple as just using a bigger cord.
 
Do I have to go to an electrician to get a 100 or 150 ft 30 amp extension cord for my fifth wheel?  I can't seem to find one on the internet.
 
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