30 amp to 50 amp extension cords

ron130fe · 07-15-2018, 03:43 PM

I’ll be going camping in a couple of weeks and the campsite has old power and limited to 30 amps and quite a few campers in my group. My question is: I want to go from the power box with a 30’ 30amp extension cord and hook it into my 35’ 50amp cord to my 5er, I’m aware that I’m limited to 30 amps I just want to know if I’ll be overloading my 30 to 50 adapter or anything else. I’m also aware that I can only run 1 AC and will try and keep as much electrical equipment down to a minimum as I can. Does anyone see a problem with this situation, I’m new to the 5er and 50amp world.

Thanks for any input

**chuckster57** · 07-15-2018, 03:45 PM

We have done what your describing on numerous occasions in the shop. I can’t say the electrical system at my work is better than the campground your going to be at. Do you have an EMS or voltage monitor?

ron130fe · 07-15-2018, 03:47 PM

Yes I have a voltage regulator 30 and 50

5J's · 07-15-2018, 03:53 PM

I'd be real cautious. If you have a good EMS you'll be fine. The issue will be voltage drop over that length. Being you're only limited to 30 Amps you should be good. If you use a GOOD QUALITY EMS you should be fine.

TheGriz · 07-15-2018, 04:13 PM

I do exactly as you are describing when I am parked at home...50A 30' cord to my 30A 50' extension to my 30A RV receptacle on my house (dogbone in between). Maybe a minimal voltage drop...1 or 2 volts at most. I am always between 123V and 115V at the TT. FYI...I do have a PI hardwired 50A EMS.

UPDATE: I just decided to check under load. Before load, the EMS read both L1 and L2 at 123V. I turned on the 15K BTU A/C unit, and the voltage still was well within the safe zone of 118V with 0A on L1 and 26A on L2.

Mike

shinobu8 · 07-15-2018, 04:56 PM

Depending on your AC type, you may be able to run both. We have a stock 15k BTU and added a second in the garage and we can run both on 30 amp.

ron130fe · 07-15-2018, 05:47 PM

How can you find the size of ac unit

ron130fe · 07-15-2018, 05:48 PM

What’s a dogbone

**chuckster57** · 07-15-2018, 05:53 PM

A “dog bone” is an electrical adapter with a male end and a female end with both ends being “different” as in the configuration (50A,30A,15A) you can pretty much get any combination. In my box I have a 50-30, 50-15, 30-15, 15-30.

**chuckster57** · 07-15-2018, 05:56 PM

Quote:

Originally Posted by shinobu8

Depending on your AC type, you may be able to run both. We have a stock 15k BTU and added a second in the garage and we can run both on 30 amp.

With only 30A TOTAL, I wouldn’t do it. Each AC unit is going to use about 13 amps when operating, leaving only 6 Amps for anything else. IF your second AC does start, I’m betting the compressor is slowly dying. Think of it as a mini heart attack, can only survive so many.

**sourdough** · 07-15-2018, 05:57 PM

Quote:

Originally Posted by TheGriz

I do exactly as you are describing when I am parked at home...50A 30' cord to my 30A 50' extension to my 30A RV receptacle on my house (dogbone in between). Maybe a minimal voltage drop...1 or 2 volts at most. I am always between 123V and 115V at the TT. FYI...I do have a PI hardwired 50A EMS.

UPDATE: I just decided to check under load. Before load, the EMS read both L1 and L2 at 123V. I turned on the 15K BTU A/C unit, and the voltage still was well within the safe zone of 118V with 0A on L1 and 26A on L2.

Mike

I know it has served you well but 80' of cable, some of questionable gauge, feeding my trailer from 30A would have me worrying a lot. Sounds like it works so...….

TheGriz · 07-15-2018, 06:28 PM

Quote:

Originally Posted by sourdough

I know it has served you well but 80' of cable, some of questionable gauge, feeding my trailer from 30A would have me worrying a lot. Sounds like it works so...….

30A...10AWG. 50A...6AWG. If I saw voltage drop, or heating at any connection I'd be concerned. Also, not pushing the amp limits, nor is the OP from what he stated. Certainly though everyone has different comfort levels.

ron130fe · 07-15-2018, 07:22 PM

Ok I have a couple of those 20-30 30-50

Thanks for great info

TheGriz · 07-15-2018, 07:39 PM

Quote:

Originally Posted by ron130fe

What’s a dogbone

Here is an example of a 50A female to a 30A male.

Alpine · 07-15-2018, 07:42 PM

Soooo can you just use a "dog bone" from the power post to your rv using only the 50amp cord? Or do you need the extra length... and that is why you would be using the 30amp cord as well? I may have missed something in translation!

**sourdough** · 07-15-2018, 07:53 PM

Quote:

Originally Posted by TheGriz

30A...10AWG. 50A...6AWG. If I saw voltage drop, or heating at any connection I'd be concerned. Also, not pushing the amp limits, nor is the OP from what he stated. Certainly though everyone has different comfort levels.

I agree..if you are happy then no worries. I wouldn't run an 80' extension cord on a 30A/50A service with multiple connections, plugs and various size cables for anything....especially mixing gauges. JMO

TheGriz · 07-15-2018, 07:57 PM

Quote:

Originally Posted by Alpine

Soooo can you just use a "dog bone" from the power post to your rv using only the 50amp cord? Or do you need the extra length... and that is why you would be using the 30amp cord as well? I may have missed something in translation!

If I understand correctly the first part of your post, you have a 50A RV and you want to plug into a 30A CG receptacle. Yes...plug the 30A male end of the dogbone into the 30A CG receptacle, and plug your 50A RV cord into the 50A female end of the dogbone. No need for the 30A extension cord unless you are too far from the CG receptacle and need the extra length.

Understand though that you are limited to just 30A in you RV when doing this.

Mike

dmorgan64 · 07-16-2018, 04:04 AM

If the box only puts out 30 amps there will be no harm to the cord adapters! You will be limited to 30 amps (usage) on the RV. Adapter shall be fine.

SummitPond · 07-16-2018, 05:06 AM

Quote:

Originally Posted by ron130fe

How can you find the size of ac unit

I had to remove the interior grill holding the filter to find the sticker with the information on it. Not sure if it is in the same place for all units.

**JRTJH** · 07-16-2018, 05:21 AM

To expand on dmorgan64's comment: If you plug a 30/50 amp dogbone into a 30 amp outlet, the dogbone is designed to support 30 amps and no harm. If, on the other hand, you plug a 50/30 amp dogbone into a 50 amp outlet, then plug the 30 amp end into a 30 amp extension cord, plug that into a 50 amp service cord (which is protected by a 50 amp breaker in the trailer, the 30 amp section of the cord is not protected and can melt, burn or be destroyed if there is a draw greater than 30 amps inside the trailer. In other words, there are no safeguards to protect the "smallest" part of the cord, the 30 amp section. All of the circuit breakers are rated at 50 amps and that section of 30 amp cord can be overloaded with no properly rated circuit breaker protection.

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