ELECTRICIANS (or others knowledgeable) please help.

[SmokelessJoe]

These are photos of the MARINCO Easy Lock power INLET used on current AIRSTREAMS.

We will install the same device on my 1976 Argosy.

The Marinco cordset , which you run from here to city or park power, is rated 30A 125v 2 pole, 3 wire.

My question is this:

What type wire should I run from the back of the device, thought the trailer, and up to the Main Breaker?

(The wiring will run through the belly pan and up through a closet to the Main.)

Same wire as the cordset? What gauge?

Somebody suggested #8 Cab Tire, 4 wire. Too much or correct?

Thanks for helping.

Sergei

[john hd]

three conductor 10 gauge type SO or equivilent would work well. very similar to the cord set.

don't forget a strain relief clamp where it enters the breaker box.

john

[SmokelessJoe]

Thanks John.

The suggestion for #8 cab tire, 4 wire came from an electrician friend who hasn’t seen the trailer.

I’m guessing that is overkill. Am I right?

Could there be any advantage to it?

Sergei

[joatmon]

Originally Posted by SmokelessJoe

... from an electrician friend who hasn’t seen the trailer?

Could there be any advantage to it?

You consulted a good electrician. He did not see how far your extenstion cord would need to be, and recommended the safest thing for your Airstream. He might go with John if he/she thinks the distance is not too far.

BTW, my extension cord is 8 gauge.

[joatmon]

Originally Posted by john hd

three conductor 10 gauge ...

Home improvement stores sell it as "two conductor with ground"

[joatmon]

Originally Posted by SmokelessJoe

.. 4 wire came from an electrician friend who hasn’t seen the trailer.

I’m guessing that is overkill. Am I right?...

4 wire is a good idea for future expansion, but only two conductors plus ground will be used for your current Airstream.

[SmokelessJoe]

Joatmon:

Thanks for all the information.

Things electrical baffle me and I’m getting confused again.

From the layman’s perspective, if the 30A cords MARINCO sells to fit their 30A inlets are 10 gauge (they are, apparently) what then would be the advantage of going #8 from the inlet box to the Main Breaker?

You are suggesting that John meant to write 2 CONDUCTOR, 3 wire, #10; not 3 CONDUCTOR, right?

Thanks again for the help.

Sergei

[joatmon]

Originally Posted by SmokelessJoe

... what then would be the advantage of going #8 from the inlet box to the Main Breaker?

You are suggesting that John meant to write 2 CONDUCTOR, 3 wire, #10; not 3 CONDUCTOR, right?

If an extension cord is too long, the electricity will suffer a voltage drop. This voltage drop could hurt your air conditioner if not accounted for. You have not posted the distance your Airstream is from shore power, so I can not comment on the right wire gauge. Your electrician friend probably has a similar sentiment. Post distances, and you may get better answers.

John is a Lineman, and knows what he talking about. Although he is a better reference than me (he does this stuff for a living), I stand behind my wording of "Two conductors plus ground".

[bhayden]

No disagreement on the wire. Never hurts to go heavier but I can't see that you need it. The big question is what sort of insulation. I assume you're going to run stranded wire and not solid? Extra insulation is I think a prudent measure in this application. I think your choices are going to be 300V and 600V and I'd go with the 600V. For extra protection and just to make life easier you might want to go with a "cord set" type wire where there's insulation and some additional mechanical strenght containing the wire bundle. The reason for the extra insulation is the movement it's going to see via flex and vibration. Chances are you'd be doing this more as a favor for the next owner but your piece of mind over the next few decades is worth something.

[john hd]

Originally Posted by joatmon

Home improvement stores sell it as "two conductor with ground"

that would be correct!

phase neutral ground... 3 wires 2 conductors and a ground.

john

[lewster]

Originally Posted by john hd

that would be correct!

phase neutral ground... 3 wires 2 conductors and a ground.

john

Sergei,

I would go with a marine grade cable. The stranding is finer, providing more surface area for the electrons to fow and it is softer and easier to work with than the standard household wire that you get at the big box stores. I agree that 8 guage is overkill and not necessary. If you plan to run an outdoor cord longer than 50', I would consider going to 8 guage for that cord to deal with the voltage drop. I have tables to calculate the drop for different wires and I can look it up if you like. Let me know.

[SmokelessJoe]

Thanks to everyone for your help with this. Combining your advice, I’ve been able to see what I should do.

Most of you understood that I was talking about REWIRING my trailer, not an extension cord. I plan to buy a MARINCO cordset to fit the new inlet.

Tomorrow I’m going to buy #10 Cab Tire, 3 wire. I’m wondering now whether “cab tire” might be Canadian usage for what you are calling 600V or SO.

It’s a heavy duty, flexible, rubber covered, indoor-outdoor, waterproof kind of wire, something like welder’s cable.

I should have you all know that I’m only running the wiring through out the trailer. I don’t want to waste an electrician’s time with that and I want poking through the aluminum shell done my way.

In the end, I will have a Master Electrician come by to connect the outlets and hook up the panel.

Many of the interior panels have been removed so he/she will be able to see the runs.

Thanks again to everyone. Mission accomplished in one day.

(I wish the wiring would go as fast).

Sergei

[john hd]

It’s a heavy duty, flexible, rubber covered, indoor-outdoor, waterproof kind of wire, something like welder’s cable.

that is perfect!

john

[bhayden]

Originally Posted by SmokelessJoe

It’s a heavy duty, flexible, rubber covered, indoor-outdoor, waterproof kind of wire, something like welder’s cable.

Welder's cable is very good stuff. You may want to check out a welding supply outfit. Likely as good or better price than a hardware store and you'll get top quality stuff like Carol/Belden/etc. Welding cable is fine stranded for extra flexibilty and the insulation is designed to be tough and impervious to all manner of solvents.

[bryanl]

Keep in mind that the fittings on most breaker boxes work best with solid wire, not stranded. Most internal RV wiring is 14/2 Romex solid stuff just like used in houses for the shorter runs.

Putting stranded wire in fittings not designed for it is not a good idea. They tend to loosen and that can cause poor connections and heat.

Wire sizing is a matter of length and maximum load. The typical 10g for 30A RV service is for 30'. You can find some charts somewhere I think. For the short run from plug to box inside the trailer, 12g would probably do but larger sizes provide a safety margin - as long as the fittings fit the wire type and size! Both the box and the plug are designed for a wire size range and type and best results are obtained if you make sure that your wire is within its spec.

[SmokelessJoe]

Bryan:

Thanks a lot.

We used 12 gauge BX armored cable thought-out.

Could I just use a 10-gauge run of that from the inlet box, through the belly pan area, up to the Main?

If we use stranded cable, which the consensus here supports, could we use a soldered or clamped on lug were the wire connects to the main panel?

Sergei

[bhayden]

Breakers for use in a house type box are made to snap onto a rail (bus) and for solid wire. There are panels, like for boats that don't do this and are designed to be more mechanically robust and provide a better contact in an environment like a boat. They have scew terminals and are designed for use with ring lugs. Crimp on lugs are good IF you buy quality crimps (I like nylon over PVC insul but both can be good) AND you use the right tool to crimp the lugs. The right tool is a ratcheting crimper, not the cheap "pliers" that you get at the auto parts store with an assortment of crimps.

PS Don't use stranded wire in a breaker designed for solid. Or vice a versa for that matter.

[lewster]

Bryan and Bernie,

Good advise about keeping stranded wire in stranded design breakers. The problem with solid wire is that in an RV situation where it is getting bumped and vibrated constantly, it eventually work hardens and breaks. I have found numerous electrical problems on RV's that were caused by a solid copper run that had broken from flexing and vibration.

[bryanl]

Lew, the problem also exists with people who solder to tin a wire to go under a lug or to solidify a crimp. Soldering is not usually a good idea for wire under a screw or anywhere near a flexing situation.

RV's are usually wired internally with household fixtures, sockets, boxes, wire, and circuit protection. These usually age fairly well. It is the interface from the internal in the wall stuff to the external world where there is more exposure to flexing and bumping and other abuse that causes problems.

Many Airstreams going back to the indedependent Airstream company era (60's) have original solid A/C house wiring in good condition.

One should also note that the 110 VAC wiring and the 12 VDC wiring have significant differences in rules, codes, practices, policies, equipment, colors, materials, insulation, and so on.

[SmokelessJoe]

Bryan:

Can I use a 10-gauge run of BX armored wire from the inlet box, through the belly pan area, up to the Main?