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Topic: Acceptable length of 50 amp extension cord (Read 5337 times) previous topic - next topic

Acceptable length of 50 amp extension cord

Hi,

When using my FT at my farm, in the past I've been parking in door of the building to access power.  This year I've developed a nice site about 100' from the building with nice shade/grass.   I didn't want to invest in trenching power to the new site which I will use seasonally, so was thinking about getting 100' of 50 A extension cord to use.   Is this distance too great for power drop or would it be acceptable.

It isn't the $$ so much as the hassle of trying to get someone out to do the trenching and hook up the new receptacle.

Thanks in advance,
Dan 1989 U280 40'

Re: Acceptable length of 50 amp extension cord

Reply #1
 The maximum RV cables for 50 amp are about 50 ft.  50 ft 50 amp RV cables are #6 wire

For 120' or so you will need a 3 conductor #3 or #2  aluminum underground feed cable plus a ground wire.  Something like this...

2-2-2-4 Aluminum Mobile Home Feeder Cable | WireAndCableToGo.com

About $1.17/ft plus shipping.  You will need a 50 amp breaker at the house end and a panel and a 50 amp breaker at the RV end plus then 50 amp RV receptacle.

6/3 with Ground copper UF-B cable runs about $4.00/ft.  This is OK for 100 ft.  More and you need to go to a #4.

Double check your local codes to be sure. Find an electrician if you are not comfortable doing this yourself.


Re: Acceptable length of 50 amp extension cord

Reply #2
Buy 100' of Romex AWG-6 or better AWG-4 and run it into lengths of inexpensive pvc pipe on top of the ground with 50 connectors.  No need to make a permanent trench for now.

Re: Acceptable length of 50 amp extension cord

Reply #3
Thanks for the replies and ideas.  I can stay 100' or slightly less.
Dan 1989 U280 40'

Re: Acceptable length of 50 amp extension cord

Reply #4
It depends on how much of a load you will be using. I use a 100 ft 30 amp cord to my rig and if I don,t use more then one electric heater I am fine. As the 50 amp cord is 220 volts and way heavier you can use a lot. As you add load you can check your voltmeter
and if the voltage stays constant you are fine. When the voltage drops you need to back off the load. 
Peter and Frieda Morin
1999 36ft. U320 Foretravel
Build # 5436
1998 Suzuki Sidekick Sport

Re: Acceptable length of 50 amp extension cord

Reply #5
basically I want the full hookup to use the normal functions of my FT (2 air, frig, etc.) but 100 ft from the plug in.
Dan 1989 U280 40'

Re: Acceptable length of 50 amp extension cord

Reply #6
I second the recommendation to go with wiring in conduit that can be buried at a later date. A "temporary" extension cord can be damaged by any number of things (including critters chewing on it) if left in place foe any length of time. In addition, it can be a hassle to roll it out when needed and then to re-roll and store it when not needed. Wiring in conduit will be protected from damage and (who knows) you may decide later that it's a good idea to dig the trench and make it a permanent setup because the site is getting more use than originally anticipated.
David and Carolyn Osborn
1995 U320C SE 40' Build 4726 Feb 1995
FMCA 147762
Motorcade 17186

Re: Acceptable length of 50 amp extension cord

Reply #7
You have to careful burying cable in conduit or even running on the ground.  Steel conduit dissipates heat much better than plastic.  Either needs to be sized appropriately for the size cable you want to use.  Conduit is generally used for individual wires.  Twisted bundles with a cover can generate more heat.   If you are 100' from the power source you have the coach's power cord to figure in so you may be able to put a post 75 or 80 ft from your source and be able to hook up the coach.  The coach doesn't use always use balanced loads so don't skimp on wire size.

Direct burial cable is designed to be buried with out a conduit.  Usually 18" deep is enough.

Whatever you do check with an electrician to do it properly. 


Re: Acceptable length of 50 amp extension cord

Reply #8
I have run 75 feet with #4 SO cable.. in Mississippi for 4 years.. wiped off the cord.. moved it with me..
Very heavy.. not an electrican, others here are

50A connections each end.. hmmm plus the coach cord.. guess that's 100 feet.. WoW
My advice and experiences are Free, you decide if they are worth anything .

John - driving Old Faithful
1994 U280 GV
C8.3, Banks, Pacbrake, 900 watts, Resonator, XLHD tow dolly
Retired Army Warrant Officer

Life is what you make of it - if it is lemons, make lemonade!
Former Coaches:
1988 GV 40' ORED 300HP CAT - 9 years
1990 Winnebago LeSharo - 3 years
2000 Newmar London Aire - 3 years (#18 of 23 produced)


Re: Acceptable length of 50 amp extension cord

Reply #9
basically I want the full hookup to use the normal functions of my FT (2 air, frig, etc.) but 100 ft from the plug in.

Start here for good info on running electrical service/voltage drops/wire size/etc.  Click on 50 amp service on the left RV Electric
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

Lifetime Escapees' member SKP 82766
Former 2003 U320 (2004-2016), current 2017 LTV Unity

Re: Acceptable length of 50 amp extension cord

Reply #10
Thanks Michelle

From the table there, 100' would require #4 for a 50A service.

From the replies above, not disputing, but wanting to learn, why would I need a 50 amp breaker again on the coach end?  I have one on the power source end, would plug in the #4 wire "extension" to that receptacle/breaker and the #4 wire into the coach 50A cord, just like at the RV park but with the "extension cord" in between.

I appreciate all the replies.
Dan 1989 U280 40'

Re: Acceptable length of 50 amp extension cord

Reply #11
I have a hard-wired progressive EMS that cuts off if the voltage gets too low. For a while I stayed at a friend's place and rand 125' of 30amp cable to a 120v 15amp outlet on his deck. I just used to charge the battery and run a small space heater on low at night.

I never had to worry about blowing his 15amp breaker because the long wire would cause voltage to drop below the EMS cutoff first! It was perfect. lol.
1998 U270 34'

Re: Acceptable length of 50 amp extension cord

Reply #12
If you are coming out of a service panel in your house you need a breaker there.  At the other end you may be able to not have a breaker, depends on local code especially if it is seen as a sub panel. It is possible that you could use a disconnct like they use outside near your AC.  A second breaker would be like they do at the RV park. It might be overkill but it is safe.  I have a breaker to the sub panel in the coach house and then breakers to each of the RV receptacle circuits.

Be safe with this.  Double check with an electrician even if you do it yourself.

Re: Acceptable length of 50 amp extension cord

Reply #13

From the replies above, not disputing, but wanting to learn, why would I need a 50 amp breaker again on the coach end?  I have one on the power source end, would plug in the #4 wire "extension" to that receptacle/breaker and the #4 wire into the coach 50A cord, just like at the RV park but with the "extension cord" in between.

I appreciate all the replies.

You do not need a breaker at the plug per any codes. It is just for convenience. It is always good to turn the breaker off before you insert the plug. If by chance you happen to connect the two phase blades before the neutral blade, bad thinks will happen to items in your coach.
2014 ih45  (4th Foretravel owned)
 1997 36' U295 Sold in 2020, owned for 19 years
   U240 36' Sold to insurance company after melting in garage fire
    33' Foretravel on Dodge Chassis  Sold very long time ago

Re: Acceptable length of 50 amp extension cord

Reply #14
Has anyone really used the full 50 amps? That's a lot of juice on each leg! Don't know, just have trouble getting that much need with our '96.
Larry
1996 U295 36'
Build # 4805
Actually we sold it but just like to lurk

Re: Acceptable length of 50 amp extension cord

Reply #15
Has anyone really used the full 50 amps? That's a lot of juice on each leg! Don't know, just have trouble getting that much need with our '96.

If your coach has 3 AC's then two would be on one phase for total of aprox. on highside  16 amps each for total of 32 amps. I would guess the microwave and the other ac on the other phase for total of 29 amps.. Then we have charger/converter, water heater, coffee pot, plus other minor items of TV's, computers and such.  So could see easy getting close to 47 amps on one phase sometime.
2014 ih45  (4th Foretravel owned)
 1997 36' U295 Sold in 2020, owned for 19 years
   U240 36' Sold to insurance company after melting in garage fire
    33' Foretravel on Dodge Chassis  Sold very long time ago