shore power contection

[Bob Gil]

is this code that is mentioned from time to time the same one that is used when building stationary houses on foundations?

[Len Silva]

is this code that is mentioned from time to time the same one that is used when building stationary houses on foundations?

Yes, it is.  The National Electric Code (NEC)  specifies "installation of electric conductors and equipment within or on public and private buildings or other structures, including mobile homes, recreational vehicles ...."

Article 551 deals specifically with recreational vehicles and parks.

The other publication you should be familiar with is NFPA 1192 which covers propane, plumbing heating and cooling etc. for recreational vehicles.

I believe very strongly in following the codes and understanding the reasons for the requirements.  I also believe that every article in the codes is a MEMORIAL TO SOMEONE WHO WAS KILLED OR INJURED by poor installation.

Len

[Sean]

Could not have said it better myself, Len.

-Sean
http://ourodyssey.blogspot.com

[Tim Strommen]

I added these to my collection this year...

NFPA 1192-2008 Edition about $35US

and,

National Electric Code 2008 (NFPA 70-2008) about $60US.

You can find the NEC 2008 edition on Amazon for about $30 used...

-Tim

[Sean]

According to my old chart you can use 4 #8 THHN wires for 50 amps in 3/4" conduit exposed to open air. It would require 1" conduit for 4 #6 THHN wires. I can't tell what size conduit is there now, but if it is 3/4" he would have to change to 1" for 4 #6 wires. My chart is based on the 1993 NEC so it may not be valid anymore.

Sam and everyone,

In my previous response to this, I allowed that I no longer had a copy of the code, and so it was hard to answer.  The reason I ditched my copy of the code was that it was an enormous book that simply did not fit on the bus with the entire rest of our lives.

I am happy to report that the NFPA now sells the code in a convenient, zero-space-requiring electronic format, and so I sprung the $75 today for a copy of the 2008 code.

And herewith is the answer:  #8 THHN, accroding to table 310-16, is rated to carry 55 amps with not more than three current-carrying conductors in a conduit.  HOWEVER, that rating only applies at 30°C (86°F).  You need to apply a derating factor to this number as the temperature goes up.  Above 104°F, #8 THHN is only rated for 47.85 amps, and above 113°F it is only good for 45.1 amps.

Bear in mind that this is the temperature at the conduit, not just the outside temperature.  So even if you never travel or camp in temperatures over 104°, if the conduit runs, say, past the engine bay, where it can get to that temperature, you need to derate.

Since 104° is not really that high in the scheme of things (we've certainly been in those temperatures many, many times, and the wiring runs through places that get hotter still), you really need to go to #6 to be safe. #6 THHN is good for 61.5 amps all the way to 122°F.

Hope that clears things up.

-Sean
http://ourodyssey.blogspot.com

[Bob Gil]

And herewith is the answer:  #8 THHN, accroding to table 310-16, is rated to carry 55 amps with not more than three current-carrying conductors in a conduit.  HOWEVER, that rating only applies at 30°C (86°F).  You need to apply a derating factor to this number as the temperature goes up.  Above 104°F, #8 THHN is only rated for 47.85 amps, and above 113°F it is only good for 45.1 amps.

-Sean
http://ourodyssey.blogspot.com

If this is the case I was planning on going with #6 any way but can I run 4 of them in the same conduit?   Since what I have looks to be water pipe and only goes about an inch past the wall behind the switch I will need to install the conduit, it looks like 1 inch conduit?

I believe that HD has the THHN #6 3 wire with a solid unchoated wire for the ground will that work?  Can I run it in conduit?  Or is it necessary to run 4 completely separate # 6 wires?

Is it true code requires a breaker within 15 inches of the entrance receptacle.

How long of a power cord should I really need?  Would 15 feet be too short? I have a 24 foot cord coming and I was thinking if I hard wire it into the switch and store it in the compartment (Same compartment just drivers side of the bus) below the bus across from the breaker switch box would this be in code?  Or would I need to run it in conduit still?

[Len Silva]

Bob, see my reply to Chaz http://www.busconversions.com/bbs/index.php?topic=8139.15

[HighTechRedneck]

If this is the case I was planning on going with #6 any way but can I run 4 of them in the same conduit?   Since what I have looks to be water pipe and only goes about an inch past the wall behind the switch I will need to install the conduit, it looks like 1 inch conduit?

I believe that HD has the THHN #6 3 wire with a solid uncoated wire for the ground will that work?  Can I run it in conduit?  Or is it necessary to run 4 completely separate # 6 wires?

Is it true code requires a breaker within 15 inches of the entrance receptacle.

How long of a power cord should I really need?  Would 15 feet be too short? I have a 24 foot cord coming and I was thinking if I hard wire it into the switch and store it in the compartment (Same compartment just drivers side of the bus) below the bus across from the breaker switch box would this be in code?  Or would I need to run it in conduit still?

Based on Sean's post, 1" conduit would be called for.  For this high power run, I prefer individual #6 wires because it allows more air around them and when I bought mine the price difference was negligible.  I don't think that is code mandated, but just my preference.  I think Sean and Len have pretty well dismissed the 15" breaker code requirement.  However like Len said it's not an bad idea, easy and fairly cheap to implement, especially since you already have the 50 amp breakers.  Just move them to their own small main breaker box in the bay.

When I set mine up, I thought a 20' 50amp shore cord would be sufficient.  Most of the time it has been.  But there have been some sites where I had to add my dogbone/30amp extension cord and settle for the 30 amp connection.

[Len Silva]

Bob, You can run 4 #6 THHN in a 3/4" conduit.  Also, you can reduce the size of the grounded conductor by up to 2 wire sizes, thus it could be #8 or #10.
So, 3 #6 and 1 #8 would work and would fit in a 3/4" conduit.

Len

[Sean]

If this is the case I was planning on going with #6 any way but can I run 4 of them in the same conduit?   Since what I have looks to be water pipe and only goes about an inch past the wall behind the switch I will need to install the conduit, it looks like 1 inch conduit?

Not only can they be run in the same conduit, they must be run in the same conduit.

If you run EMT (metal conduit), flexible metal conduit, or Schedule 40 PVC, you can get four #6 in a 3/4" pipe.  If you run ENT (smurf tube), you'll need 1" for four #6.  You might be able to do three #6 and one #8 in a 3/4" smurf tube -- someone would need to do the actual fill calculation since the tables only show same-sized conductor fill.

I believe that HD has the THHN #6 3 wire with a solid unchoated wire for the ground will that work?  Can I run it in conduit?  Or is it necessary to run 4 completely separate # 6 wires?

If you're talking about a cord assembly, that's probably not what you want.  If you're talking about NM ("Romex®") or armored cable such as BX, then those are fine and would be run without conduit, as long as they are secured and use proper fittings.

In conduit, you'll need to use separate insulated conductors.

Is it true code requires a breaker within 15 inches of the entrance receptacle.

No, I think we've finally debunked this myth.  I don't know where it started.

How long of a power cord should I really need?  Would 15 feet be too short? I have a 24 foot cord coming and I was thinking if I hard wire it into the switch and store it in the compartment (Same compartment just drivers side of the bus) below the bus across from the breaker switch box would this be in code?

If you hard-wire to a box in a compartment, 24" will be too short.  Code now requires a 25' cord if it enters on the side of the bus within 15' of the rear.  For every foot further forward than 15' your cable entrance is, you need to add another foot to the cord.  Also, I can tell you from experience that you'll have trouble hooking up in a lot of places if you ignore this part of the code.  We carry a 6-gauge, 50-amp, four-wire extension cord 50' long, in addition to our 25' shore cord, and we've needed to use it several times.

HTH,

-Sean
http://ourodyssey.blogspot.com

[Bob Gil]

If you're talking about NM ("Romex®") or armored cable such as BX, then those are fine and would be run without conduit, as long as they are secured and use proper fittings.

If I did use the BX I think it was I was looking at how should it be secured and what are the proper fittings?  As you can tell I do not know much about this stuff.

If you hard-wire to a box in a compartment, 24" will be too short.  Code now requires a 25' cord if it enters on the side of the bus within 15' of the rear.  For every foot further forward than 15' your cable entrance is, you need to add another foot to the cord.  Also, I can tell you from experience that you'll have trouble hooking up in a lot of places if you ignore this part of the code.  We carry a 6-gauge, 50-amp, four-wire extension cord 50' long, in addition to our 25' shore cord, and we've needed to use it several times.

HTH,

-Sean
http://ourodyssey.blogspot.com

Looks like I bought a 24 foot 6/4 with 50 amp plug, that I will need to make a extention cord out of.  I guess I can go a head and buy the 36 footer I was looking at and have what I might need then.

Looks like I am going to have to slow down on this project and let the cash catch up a little.  Mama  is not going to like it.

[Len Silva]

Actually, I don't think BX exists any longer.  You are looking for type MC (metal clad) which comes in both steel and aluminum jacket.  The aluminum is much easier to work with, the steel is more protective from crushing forces.  There is also a limited bend radius when using this.  You can finf type MC and the proper fitting at HD

[HighTechRedneck]

Looks like I bought a 24 foot 6/4 with 50 amp plug, that I will need to make a extension cord out of.  I guess I can go a head and buy the 36 footer I was looking at and have what I might need then.

Looks like I am going to have to slow down on this project and let the cash catch up a little.  Mama  is not going to like it.

If I may suggest, use the 24' one for now.  Get the longer one later.  Not that hard to switch them later.  Try to keep working on it, even if slower.  That way you still make progress and you don't lose interest.  If you can get it to a point where it is safely usable, take it out for a weekend, even if only to a local campground.  Enjoy it.  That will refresh your enthusiasm for it.

[DrivingMissLazy]

Bob, In all my years of travel I do not think I ever needed the full 25 foot of the 50 amp shore cord I had. I can assure you that the majority of campgrounds that you will visit that the camp ground outlet will be closer than 25 ft.

Richard

[Bob Gil]

I am trying to get some ting done with this thing.  It seams like the more I do the behinder I get.  All I do is find stuff that I was not expecting to find that will have to be delt with before I can do some thing else.

I have gotten the burn't part out of the engine compartment, and replaced some of the wood in the front of it.  I have the alumin sheet to put up over it then i can start mounting the hard ware to start the engine compartment rewire.

I have got the material to rebuild the bed after I get that done the way I want it. 

I hope to get the electrical where I can pulg it up and run the ref a little and maybe a radio and such.

I has been a slow go not knowing what I was up against.  I still have not found any info on the gauges for the dash.  Hope I can find out some thing before I get that far along.  Hope I get there with in the next week.