50 amp receptacle breaker: 60 amp OK?

[peggwn]

OLYLEN and all others, I need to amend my statement. Please hold all the comments I know you were ready to fire off. We will not be using an adapter at home. I should have said we will (for emphasis) install a 30amp service receptacle to plug in our 30amp RV. We shall use heavier wiring to support a 50amp service receptacle should we need 50amp service in the future. Our electrician has suggested 3 strands of #6 now for the 30amp service. We'll bury it about 18"-24" deep in 1" conduit on a 65' run from the house. Sorry for the confusion.

[Dr4Film]

Originally Posted by peggwn

Our electrician has suggested 3 strands of #6 now for the 30amp service. We'll bury it about 18"-24" deep in 1" conduit on a 65' run from the house. Sorry for the confusion.

You will need to have 4 strands of #6 unless you plan to leave a "pull" cord in the conduit to pull the 4th strand later if 50 amp is needed.

30 amp is three wire, Hot, Neutral, Ground.
50 amp is four wire, Hot-L1, Hot-L2, Neutral, Ground.

Dr4Film ----- Richard

[John Hilley]

Although 1" conduit is sufficient for 4ea 6 awg wires, I would use 1 1/4" for ease of pulling, it won't cost much more. You will need 4 wires if you change to 50 amp in the future.

[nothermark]

Originally Posted by NormDunn

Thanks, I looked at and liked the link. Upon reading it I quickly noticed they were talking about a/c circuits and motor load circuits and not a multipurpose circuit. Personally, I don't believe and it has not been my experience that any electrical inspector has, would, will allow a 20A breaker on a comercial, residential or rv circuit that is not specifically dealing with a dedicated ac or motor circuit. Again, that's just been my experience.

I like to think of any code book as the absolute worst job you can do and still get a green tag.

The use of the circuit is irrelevant to the ampacity of the wire. It's all about line drop and heat generation. You can regard it any way you want to but I have always seen the code as a lot closer to the ideal job than the worst job. Put 30 A through 18 GA bell wire if you want bad jobs. You might find this table interesting:

Fusing Currents versus American Wire Gauge for copper, aluminum, iron, and tin (Cu, Al, Fe, Sn), wire melting currents

It was a common practice to use enameled or uninsulated wire links as a fuse in the old tube gear for things like filament lines. It is still done in the automotive industry for things like the fusible links in high current 12 V systems. That tends to calibrate one's expectations over how much current can flow down a wire and expect things to keep working.

[TQ60]

Others stated 4 wires required.

And big cost is the labor

Adding things now adds little material cost and little labor.

So...

What to do...?

Get a small sub panel as they are CHEAP and often come with breakers.

Pull wire rated for 60 amps or more and use correct breaker for this at main.

Place sub panel in general area near mh.

Now install a 30 amp outlet on a breaker for need now.

Install a 50 amp outlet now for later.

Install a gfi 120 vac outlet for general use.

Install additional outlets for things like battery charger by the battery bays.

Maybe some lighting too.

Cost for sub panel and outlets with other goodies about $100 or less and additional labor to install them now maybe an hour or diy.

[ImagineIF]

Nothing down stream of a breaker before another breaker is in line can be rated at anything less than the breaker. So, someone putting in an outside 50A outlet would need to limit the breaker in the main breaker to 50A or less and the wire gauge must support the rating of the breaker.

If you want to have a 50A and 30A outlet at your outside location, the outside box would then require a 30A breaker for the 30A outlet. A 50A breaker would be required at the external box, if the breaker from the main breaker is greater than 50A. Remember, if the main breaker is greater than 50A then the wire between the main breaker and external box breaker(s) must support the current of the main breaker.

An adapter that takes 50A from the pole an pushes it down a 30A RV power cable would require a 30A breaker in the adapter. An adapter from 30A to a 50A RV cable would not require an additional breaker.

[TQ60]

That is why subpanel is suggested.

About 30 to 40 bucks with some breakers.

30 and 50 amp 2 pole would be extra at about 20 bucks or less each.

[ImagineIF]

I should have added, that unless the outside outlet is very near the main breaker box I would use a sub panel. My RV pad is almost 100 feet from my house. I have a sub panel with a 50A and 20A breaker and a 50A RV outlet and 20A GFCI outlet. The complete box cost about $60.

[NormDunn]

Originally Posted by nothermark

The use of the circuit is irrelevant to the ampacity of the wire. It's all about line drop and heat generation. You can regard it any way you want to but I have always seen the code as a lot closer to the ideal job than the worst job. Put 30 A through 18 GA bell wire if you want bad jobs. You might find this table interesting:

Fusing Currents versus American Wire Gauge for copper, aluminum, iron, and tin (Cu, Al, Fe, Sn), wire melting currents

It was a common practice to use enameled or uninsulated wire links as a fuse in the old tube gear for things like filament lines. It is still done in the automotive industry for things like the fusible links in high current 12 V systems. That tends to calibrate one's expectations over how much current can flow down a wire and expect things to keep working.

I am familiar with this table. This is for bare conductors in open air, outside, pole to pole or some other attachment means. Means absolutely nothing with respect insulated wire.
After 40 yrs in the electrical industry, owner of Dunn Electric INC - Commercial, Industrial, Residential Const., Maint., Repair. Owner of Northlake Transmission - High Voltage Const., Maint. Repair, 46kV to 500kV. Licensed Journeyman Electrician, Licensed Journeyman lineman, Certified in live line maintenance thru 500kV, along with other certifications. Your qualifications may in fact exceed mine and that's great however, I'll stick with my opinion of the code which is the code is not the ideal installation. It's an installation that meets the minimum requirements outlined by the code and is acceptable and will provide a level of reliability and safety but not necessarily ideal.
Thanks..
Norm..

[nothermark]

The only reason I quoted the fusing table is the claim that the wire would melt. It will not even come close to warming up the insulation. The circuit is rated for more than the 50 A for the camper. The only line in question is the cable from the receptacle to the camper. The line from the panel to the receptable is already 60 Amp and the camper pigtail may also be 60 A depending on the type of insulation.

Can't say I ever ran in electrical contracting business. I did run a bunch of tests on conductor heating and why we had to us various gauge wires and insulations. Fire Underwriters is very conservative in their ratings.

[Mentor]

Originally Posted by OLYLEN

Perhaps the experts can tell me why your panel at the S/B has a 200 amp main that ends at 15 amp breakers and it's OK. And a 30 amp RV can use a 50amp post with a cheater and it's OK, but not use a 60amp to a 50 amp.

LEN

The 200 amp supplies all the circuits and all connections (the bus bars) between that 200 amp main and the 15 amp breakers is rated 200 amp, from the 15 amp on everything is rated 15 amps, thus everything is covered safely.

Those breakers allow you to pull the full 200 amps but if you go over it will trip. An old breaker may not be able to carry the full 200.

Think of it like pipes, the voltage is the pressure and you can only have 125 or 250, the amperage is the volume of flow, when you need more flow you need to increase the pipe size and the valve size (the breaker) or increase the pressure (voltage) which you cannot do in RV or household applications so you increase the volume (amperage)