Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×


Reply
 
Thread Tools Display Modes
 
Old 10-23-2015, 09:45 PM   #121
Bus Nut
 
Join Date: Aug 2015
Posts: 308
Quote:
Originally Posted by OMGIBoughtABus View Post
SJO does not dissipate heat very well, the amperage ratings for 3 prong cords are assuming open air cooling.

For a permanent installation, and if I'm going to enclose the wiring in foam (inside of conduit) I would not use an extension cord.

I also wouldn't use extension cords for appliances with a high draw.
How much draw can you really expect in a bus? I don't foresee anyone using a kiln or welder plugged to the inside of their bus for very long. If you are running cooking stuff they should really be put on their own high amperage circuit anyways (20A+). I would put AC units on 10 gauge. Max run length can't really be longer than 96 feet (that is circumnavigating the bus) which would be dumb on anything larger than a 15a circuit, no on second thought that would just be dumb period.

I will admit I am of the camp that thinks the multi strand will help with the constant earthquake of driving over the heat dissipation of single wire. I feel deep down that there won't be that much difference between either in the long run. Bad idea bear says just fill the conduits with transformer oil.

CaptainInsaneo is offline   Reply With Quote
Old 10-23-2015, 09:52 PM   #122
Skoolie
 
OMGIBoughtABus's Avatar
 
Join Date: Aug 2015
Location: The Lovely PNW
Posts: 145
Year: 1986
Coachwork: Thomas
Chassis: Saf-T-Liner
Engine: Cat 3208
Rated Cap: 84 px
Quote:
Originally Posted by CaptainInsaneo View Post
How much draw can you really expect in a bus? I don't foresee anyone using a kiln or welder plugged to the inside of their bus for very long. If you are running cooking stuff they should really be put on their own high amperage circuit anyways (20A+). I would put AC units on 10 gauge. Max run length can't really be longer than 96 feet (that is circumnavigating the bus) which would be dumb on anything larger than a 15a circuit, no on second thought that would just be dumb period.

I will admit I am of the camp that thinks the multi strand will help with the constant earthquake of driving over the heat dissipation of single wire. I feel deep down that there won't be that much difference between either in the long run. Bad idea bear says just fill the conduits with transformer oil.
Bad Idea Bear he's the lead designer on my project
__________________
����
OMGIBoughtABus is offline   Reply With Quote
Old 10-23-2015, 10:08 PM   #123
Bus Crazy
 
Join Date: Feb 2012
Location: Salt Lake City Utah
Posts: 1,635
Year: 2000
Chassis: Blue Bird
Engine: ISC 8.3
Ampacity/wire gauge is easy enough, though I just learned tonight from the EC&M reference I'll cite later, that flexible cord ampacity should be derated when ambient temperature is above 86 F.. I hadn't realized that! IMHO that's likely inside the walls of a skoolie in the summer.

Wiring with extension cords is a subject of much debate, sometimes rising to religious fervor here on skoolie.net. This conversation is about the insulation over the wires, not their gauge. I'm also not going to call anybody out, say they're absolutely doing it wrong, etc etc because it's just not a war I'm interested in waging. (I haven't been keeping score as to who has used what, either.) My earlier comment and photo with the damaged wire, as well as the following, are the rationale behind my intention to use conventional home/building wiring methods in my skoolie. I found several interesting references through a search that began with the phrase "portable cord permanent wiring."

Through inspection and handling, the insulation and jacket on normal extension cords is seen relatively soft, pliable.. and easily cut. It seems like a good thing to have out in the open, where physical damage can be easily discovered. It's the old conventional wisdom "don't run a cord under a rug."

Mike Holt is a recognized name in electrical wiring circles. He contributed an article to EC&M Magazine Flexible Cords, Cables and Fixture Wire which does a nice job of explaining to industrial maintenance people how NEC permits use of flexible cords, aka extension cords. In his words, summarizing NEC, "flexible cords must not be: used as substitutes for the fixed wiring of a structure, ..." The article is fairly short and an interesting read.

For 120-volt systems, the RVIA standard is NFPA 70, aka National Electrical Code, and it specifically calls on articles 551 and 552.

I think this is a relatively new thing: NFPA allows free access to their standards on their web site. It's a clunky online web viewer designed to making copying the text difficult, but it's not SOOO bad.. This link might work to take you there. One has to register for a free account and agree to terms & conditions to gain access to the docs.

Article 551 is for RVs. Section 551.47(A) "wiring methods" calls out cables and raceways in accordance with (blah blah blah) in articles in the 300's (note from Mike Holt's article that flexible cords are treated in the 400's). Section 551.47(P)(1) is for "direct wired expandable units" -- slide-out rooms, if I understood correctly. It does call for "flexible cord" in this scenario, but with very specific installation requirements to protect the cord and to limit the spread of fire in case the cord does have a problem. Its separate mention for this specific use implies to me that flexible cord doesn't belong in other places in the RV.

So anyway, with all that said: I might use NM "Romex" cable, but probably I'll be using THHN/THWN, likely of the stranded variety, when I finally get to that point. Probably in hard PVC conduit. I just wish I knew of some decent conduit-friendly plastic junction boxes. The outdoor boxes are $$$, the boxes for the ENT "smurf tube" conduit are too hard to find with any sort of variety.. and using steel boxes with plastic conduit seems like a lousy idea.
family wagon is offline   Reply With Quote
Old 10-24-2015, 09:11 AM   #124
Bus Nut
 
charles_m's Avatar
 
Join Date: Sep 2013
Location: Denver
Posts: 489
Year: 1982
Coachwork: Blue Bird
Chassis: International S1800
Engine: DT466 Trans: MT643
Rated Cap: 65
Looks like Im dying in an electrical fire. At least I tried to do it all right!

Even if my 12/3 was derated by over 20%, id still be well in the clear.

I do have the piece of mind of knowing that the kind of wire my bus came with from the factory is closest to the stuff i used and not romex-type stuff. I wouldn't put solid wire in a bus, either. I guess I'm still happy with my choice.

So much of this is code based and anecdotal. I wish someone with some money and time would hurry up and do a study already
__________________
Patina enthusiast and professional busman
www.bustoshow.org
Blog: www.lookatthatbus.com
Instragram: @lookatthatbus
charles_m is offline   Reply With Quote
Old 10-24-2015, 10:06 AM   #125
Bus Geek
 
Tango's Avatar
 
Join Date: Mar 2011
Location: Houston, Texas
Posts: 8,462
Year: 1946
Coachwork: Chevrolet/Wayne
Chassis: 1- 1/2 ton
Engine: Cummins 4BT
Rated Cap: 15
One basic consideration in wiring a bus, RV, truck, anything that will be bounding & bouncing over the roads is...the use stranded wire vs solid. Solid copper wire will work harden fairly quickly when exposed to constant vibration and can give it up pretty quickly. Virtually every vehicle made in the last hundred years uses only stranded wire for just that reason.
Tango is offline   Reply With Quote
Old 10-24-2015, 12:20 PM   #126
Mini-Skoolie
 
LRflip's Avatar
 
Join Date: Aug 2015
Location: Estes Park, CO
Posts: 67
Year: 1994
Coachwork: AmTran
Chassis: B700
Engine: 5.9L 12V Cummins
Rated Cap: 71 Passenger
keep up the debate boys, I want some damn answers.
__________________
I don't negotiate with terrorists...or Canadians.
LRflip is offline   Reply With Quote
Old 10-24-2015, 04:26 PM   #127
Bus Nut
 
Join Date: Aug 2015
Posts: 308
It is the choice of 2 evils. One if a strand breaks nbd the other if one breaks it is done. my suggestion is to over size the gauge of the in wall wire by at least one whole gauge if you are going to use multi strand wire. I say this for 2 reasons, 1 a larger diameter wire will have more copper and act as a bigger heat sink. 2 larger diameter will have lower resistance meaning less heat build up. I plan on going to home depot or wallyworld and getting the longest biggest extension cord that they have that will probably cost in the $1-1.4 per foot range. I plan on laying out the electrics putting the electric control panel in a place that is central to the distribution and not effecting other systems. I can't really see needing more than 150 feet of wire.
CaptainInsaneo is offline   Reply With Quote
Old 10-25-2015, 01:18 PM   #128
Bus Crazy
 
Join Date: Nov 2011
Location: Sault Ste. Marie, Ontario
Posts: 1,791
Year: 1997
Coachwork: Thomas
Chassis: B3800 Short bus
Engine: T444E
Rated Cap: 36
I wanted to use this, but couldn't find it locally: Ancor - Triplex Boat Cable


I'm ok with the solid 12/3 I used since it's encased in the spray foam (except for the device boxes, of course), but the boat cable would have been nicer all around.
__________________
My build page: Armageddon - The Smell of Airborne Rust
jazty is offline   Reply With Quote
Old 10-25-2015, 05:34 PM   #129
Bus Nut
 
Join Date: Aug 2015
Posts: 308
If boats use multi strand wire then that settles it for me. Fire on a boat = death, pure and simple.

Often you hear people talk how over built things are for boats, it is because failure of even a hatch on the open sea can lead to death. Therefore you can't have failures, If given the chance build it like a boat. I don't know if we need tinned wires in skoolies but that is cool. I have bookmarked that page for future reference.

I also want to point out I don't think it is wrong or abhorrent to use romex. Your rig won't explode from using it and it more than likely won't fail, your screws might loosen on the terminals over the course of 10000 miles though. I will also say I have never heard a compelling reason other than money not to use oversized wires.

As a side note the more I hear about the RVIA and industry standards, the less I care what their accepted practices are. Mainly RVs are designed to be used probably no more than one weekend a month 8 months out of a year for 10 years or a total usage of about 200 days spread over a decade. I don't care if that is all you plan on using your skoolie for, I want people to build like you are going to live in it everyday for the next 2 decades. It won't cost that much more to do and it will never fail you or the next owners.

Also this place sells it too, their price make me rethink using simple extension cords.
Marine Cable - Tinned
CaptainInsaneo is offline   Reply With Quote
Old 10-25-2015, 11:16 PM   #130
Bus Crazy
 
Join Date: Nov 2011
Location: Sault Ste. Marie, Ontario
Posts: 1,791
Year: 1997
Coachwork: Thomas
Chassis: B3800 Short bus
Engine: T444E
Rated Cap: 36
Yes, I should have mentioned that there are many suppliers of the triplex boat cable. Any marine store worth its salt () will have some in their suppliers catalogue. I've seen it come untinned as well
__________________
My build page: Armageddon - The Smell of Airborne Rust
jazty is offline   Reply With Quote
Old 10-26-2015, 11:41 AM   #131
Bus Crazy
 
Join Date: Feb 2012
Location: Salt Lake City Utah
Posts: 1,635
Year: 2000
Chassis: Blue Bird
Engine: ISC 8.3
Quote:
Originally Posted by CaptainInsaneo View Post
As a side note the more I hear about the RVIA and industry standards, the less I care what their accepted practices are.
I expected somebody would bring this up. To a large degree I feel the same way: sticks and staples seems a terrible way to build a vehicle. And I'm not concerned about maintaining minimum separation distance between my shore power, city water connection, and holding tank drains because I think I can manage not getting the connections mixed up. Those are just the first two areas that come to mind where our non-compliant ways here are perfectly acceptable to me/us!

Quote:
Originally Posted by charles_m View Post
Looks like Im dying in an electrical fire. At least I tried to do it all right!

So much of this is code based and anecdotal. I wish someone with some money and time would hurry up and do a study already
Oh come on, like I said in the beginning I'm not calling anybody out and not proclaiming it'll all end in ruin if done any other way. There's a good chance nothing bad will happen.

As far as someone with time and money doing a study: that's what NFPA is all about. Sometimes I feel like they go to extremes, but they are THE organization that studies fire and electrical safety.

Quote:
Originally Posted by CaptainInsaneo View Post
the longest biggest extension cord that they have that will probably cost in the $1-1.4 per foot range. I plan on laying out the electrics putting the electric control panel in a place that is central to the distribution and not effecting other systems. I can't really see needing more than 150 feet of wire.
I truly don't know why NFPA, OSHA, and virtually every other safety organization disapprove of extension cords used as permanent wiring. Note that they're not saying to use solid wire -- stranded is perfectly fine by them, just not in the form of an extension cord. A budget of $1-1.4 is sufficient for black rubberized SO-type cable which has much tougher insulation than run of the mill cord. It's also enough for the marine cable jazty linked to, or for stranded THHN/THWN in conduit.

LRflip: See, I warned you it is a hot topic! But we all manage to be friends and enjoy the hobby together anyway.
family wagon is offline   Reply With Quote
Old 10-26-2015, 03:47 PM   #132
Bus Nut
 
Join Date: Aug 2015
Posts: 308
I can tell you why they disapprove of them as permanent wiring, for starters it is a lot easier to put a nail through them (I don't see any of us hanging too many pictures in a bus and solved by use of conduit). From personal experience I do feel there is a difference in carrying capacity at the smaller end of the gauge spectrum (16/3). If pushed too hard the higher flexibility will allow for easier contact between strands if insulation melts. That said I think that would be reallllllly hard to do in a bus as there just isn't space to hook up your induction crucible and we don't run enough 220 circuits inside the bus to worry about welders nor is there room to to use 4 hair dryers in any bathroom in an RV. If you have a lady friend who needs to have a blow dryer, curling and flat iron plugged in at the same time plan accordingly and run 2 or more circuits to the bathroom, or get a new lady friend.

I will concede that there are plenty of common sense rules in the RVIA standards, but you wold have followed those anyways, and those that you won't don't matter because you designed them and are fully aware about the issues they could pose.

I really feel that one should treat a bus build like a boat build, lets face it a 40' motor home is a land yacht. While we don't have to worry about drowning if we have to abandon ship, we should still take every reasonable step to ensure that we shouldn't need to. I also suggest using the heavy duty sockets they really do grip the plugs better and if you have something plugged in as you are driving you don't want it to get unplugged due to road vibration.

Quote:
Originally Posted by jazty View Post
Yes, I should have mentioned that there are many suppliers of the triplex boat cable. Any marine store worth its salt () will have some in their suppliers catalogue. I've seen it come untinned as well
No the tinning might actually com in handy in a situation of it over heating as it will melt and help dissipate the heat a bit better, of course if that happens you would probably need to replace the wire anyways, but hey it might help avert a fire. Not to mention the high humidity RVs are known for.

I get the feeling it is like a catholic/ protestant type debate, and really in the end comes down to personal faith and politics.
CaptainInsaneo is offline   Reply With Quote
Old 10-26-2015, 05:19 PM   #133
Mini-Skoolie
 
LRflip's Avatar
 
Join Date: Aug 2015
Location: Estes Park, CO
Posts: 67
Year: 1994
Coachwork: AmTran
Chassis: B700
Engine: 5.9L 12V Cummins
Rated Cap: 71 Passenger
Quote:
Originally Posted by jazty View Post
I wanted to use this, but couldn't find it locally: Ancor - Triplex Boat Cable


I'm ok with the solid 12/3 I used since it's encased in the spray foam (except for the device boxes, of course), but the boat cable would have been nicer all around.
This is sexy, I must have it in my bus.
__________________
I don't negotiate with terrorists...or Canadians.
LRflip is offline   Reply With Quote
Old 10-26-2015, 05:51 PM   #134
Mini-Skoolie
 
TheLovelyBus's Avatar
 
Join Date: May 2015
Location: Washington
Posts: 25
Year: 1993
Coachwork: Blue Bird
Chassis: International
Engine: DT466
Can't you use regular outlet boxes with Smurf tube? They sell special snap together fittings for it, but you can also solvent weld regular PVC conduit fittings to it if I'm not mistaken. My intent is to do all 120VAC wiring that is in wall or otherwise concealed with stranded THHN in Smurf tube, and then transition to EMT with the cheap metal boxes for visible, surface mounted stuff. The EMT is for aesthetics although there is the bonus that it meets code.

The shore power feed cable will be SJOOW, probably 10/3 with a 30A plug, but that's a personal choice based on expected amperage.

I considered the extension cord route, and I am in the camp that says it will be okay if you use good heavy gauge ones and derate. But cheap extension cords are mostly 16AWG with flimsy insulation - when I priced it out, I found that the cost to buy new 10AWG or 12AWG extension cords for house wiring use was comparable to running THHN in Smurf tube, which gives better protection and is NEC compliant.

Romex is most likely the cheapest option. There's been lots of discussion about whether solid wire is really appropriate in a moving vehicle, so I'm using stranded out of an abundance of caution. But lots of factory RVs use it.
TheLovelyBus is offline   Reply With Quote
Old 10-26-2015, 06:42 PM   #135
Mini-Skoolie
 
ArmyChap's Avatar
 
Join Date: Sep 2014
Location: Fort Riley, Kansas
Posts: 42
Quote:
Originally Posted by CaptainInsaneo View Post
I get the feeling it is like a catholic/ protestant type debate, and really in the end comes down to personal faith and politics.

Finally, something I can speak intelligently on!
ArmyChap is offline   Reply With Quote
Old 10-26-2015, 06:56 PM   #136
Bus Geek
 
EastCoastCB's Avatar
 
Join Date: Sep 2014
Location: Eustis FLORIDA
Posts: 23,764
Year: 1999
Coachwork: Thomas
Chassis: Freighliner FS65
Engine: Cat 3126
Rated Cap: 15
Quote:
Originally Posted by CaptainInsaneo View Post

I get the feeling it is like a catholic/ protestant type debate, and really in the end comes down to personal faith and politics.
So- six of one, half dozen of the other?
EastCoastCB is offline   Reply With Quote
Old 10-26-2015, 08:23 PM   #137
Bus Crazy
 
Join Date: Feb 2012
Location: Salt Lake City Utah
Posts: 1,635
Year: 2000
Chassis: Blue Bird
Engine: ISC 8.3
Quote:
Originally Posted by CaptainInsaneo View Post
I also suggest using the heavy duty sockets they really do grip the plugs better and if you have something plugged in as you are driving you don't want it to get unplugged due to road vibration.
You said lots of good things in your post, but this one was best of all. So often people reach for the bulk bin of 70-cent duplex receptacles not realizing that on the shelf above in neat individual boxes there are vastly superior alternatives. Nylon construction instead of phenolic, much better terminals on the inside and also better terminal options on the outside. Yeah, they cost a few dollars more, but so worth it in locations like kitchen, bathroom, and garage/workshop where things are plugged and unplugged frequently and/or they may be treated a bit roughly.
family wagon is offline   Reply With Quote
Old 10-26-2015, 10:48 PM   #138
Bus Nut
 
Join Date: Aug 2015
Posts: 308
They are worth it everywhere, even in your house. If you ever have to install/replace one, replace it with a heavy duty one.
CaptainInsaneo is offline   Reply With Quote
Old 10-27-2015, 08:52 AM   #139
Bus Nut
 
Join Date: Aug 2014
Location: Connecticut
Posts: 262
Year: 2003
Coachwork: International
Chassis: Amtran
Engine: T444E
Rated Cap: 71
Gfi

Magnum inverter manual recommends using GFI circuit protection, surprised there has been no mention of this?
__________________
"This is my ship...the Nebuchadnezzar, it's a hovercraft."
~Morpheus
The Nebuchadnezzar is offline   Reply With Quote
Old 10-27-2015, 12:56 PM   #140
Mini-Skoolie
 
LRflip's Avatar
 
Join Date: Aug 2015
Location: Estes Park, CO
Posts: 67
Year: 1994
Coachwork: AmTran
Chassis: B700
Engine: 5.9L 12V Cummins
Rated Cap: 71 Passenger
Quote:
Originally Posted by The Nebuchadnezzar View Post
Magnum inverter manual recommends using GFI circuit protection, surprised there has been no mention of this?
All, I repeat, All of my duplex receptacles will be GFCI protected.

I don't screw around with electric shock or electrical fires...I've been on too many jobsites, been through too many safety classes and had my OSHA 30 for too long to risk dealing with any of these hazards.

I kinda thought it was a given.
__________________
I don't negotiate with terrorists...or Canadians.
LRflip is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 09:35 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2024, vBulletin Solutions, Inc.