120 Volt System

[richard5933]

I didnt know toasters cam any larger that 15 amps.

Even if what you're saying is true, shouldn't a 15-amp toaster be used on a 20-amp circuit? I've been taught never to run more than 80% load on a breaker. If you have a 15-amp appliance you really should install a 20-amp circuit.

[sledhead]

the building code is slowly changing for new construction

in Ontario Canada the kitchen is the only room in the house that needs 20 amp recepticals and some have to be gfci

wow and my coach has had 20 amp recepiticals on all and it's 22 years old

a lot of hand held hair driers are 1875 watts hows that work in a 15 amp receptical
can you say

" it's all I got captian it's at maximum wrap "

[Jim Blackwood]

1875 watt heaters used to be the standard plug-in item. That was the most you could run on a 15 amp outlet, actually 75 watts oversize but it generally worked. Now it seems 1500 watt is more common. Perfect example of why 12 ga wire should be used for outlet service. Safer to overbuild just a bit.

Jim

[chessie4905]

The building code and electrical code is a big scam anymore. The people that make the changes are paid and come up with changes every year to justify their jobs. A few changes and new regulations manuals have to be printed, which contractors and code enforcement officers need to buy to keep up with latest changes. Millions made by printing industry, Millions spent by contractors, millions spent by new home buyers. Osha almost as bad. It never ends.
And no wonder building costs keep going up. And won't  even get into permitting and environmental requirements. Government is resistant to raise taxes as much. Just raise fees and extract more money from businesses. Less chance of voter risk this way.

[richard5933]

Building codes and electrical codes aside, running any electric device at or near its design limits isn't a good idea. Things like circuit breakers wear out, have faults, etc. They can wear faster if they are tripping frequently, causing a spiral of even more frequent tripping and even more wear. Wiring connections in a moving bus also are prone to developing faults, no matter how careful we are in putting things together. Overbuilding and using 20-amp circuits with 12-ga wiring in place of 15-amp/14-ga wiring seems like an easy enough way to build in a little operational buffer.

[chessie4905]

Especially important when staying at campgrounds on the pole and voltage runs low, increasing amperage draw from electrical loads. Actually, even at home sometimes when plugged in. Make sure the wiring used in coach is made with solid copper and not copper clad aluminum.

[sledhead]

I have argued with my power co. at home because the pole power to my house is at best 119-120v and when there is a lot of draw it sure can drop fast . they think that 6 homes that run off one pole mount transformer is fine . me not so much but they refuse to change it .

here in Florida I get 125 v all the time and the higher the volts the better it is on some of the applinaces 

[chessie4905]

I've heard they can change tap connections at transformer to up the voltage a coupledigits. Don't  know if that is true or not.

[Jim Blackwood]

Just a short note, on your outlet runs with 12 ga wire, get the higher rated outlets. The 59 cent specials are a false economy. You won't have enough outlets in the bus to make a difference so spring for the box of 10 at a couple bucks apiece with the 30a rating just for peace of mind.

Jim

[fortyniner]

never understood why most cube type heaters have such a small gauge wire to the plug . it gets warm if you use the heater on high . for that reason I never leave the coach with a cube heater on hi and low or 1/2 power is a lot safer

The cord on those devices is often a special type that is designed to limit the maximum draw.  Some are not even copper but some sort of nickel type wire.

More circuits with smaller breakers can provide a safety factor.
For example a device  shorts a 30amp will probably turn it into a welder whereas a 15amp would likely trip.

For a 1800 watt heater 14ga wire is fine up to 15feet. A single 20amp breaker for this load protects the wiring for over heating and would trip if heater shorted.

Generally sizing the wire for a drop of 2-3 volts under full load is fine.

This is a fun wire gauge calculator for what if questions:
https://www.calculator.net/voltage-drop-calculator.html

[sledhead]

ya
it looks to me like the cord on the heater is just old 2 prong light wire ? yet the cord on our 16" floor fan is 3 wire 14 gauge cord ? a lot bigger and a pain to coil up but I am sure there is a csa stamp on both of them

" so they are safe "

[Glennman]

Just a short note, on your outlet runs with 12 ga wire, get the higher rated outlets. The 59 cent specials are a false economy. You won't have enough outlets in the bus to make a difference so spring for the box of 10 at a couple bucks apiece with the 30a rating just for peace of mind.

Yep, for sure. The cheapies are only 15 amp.

[mqbus767]

Glenn,

Just because you mentioned you already have some wire lying around that you intend to use...make sure you're wire is stranded, not solid. The vibrations in a bus will fatique solid wire at the connection points and you may find yourself chasing gremlins after a bit.

[Jim Blackwood]

Well here we go, that's the other thing. Stranded wire brings an entirely different methodology with it. Definitely safer for vehicles if done right. BUT, don't wire your bus with THHN.

It's made to be run through conduit in stationary applications for industrial equipment. The outer (clear) layer of insulation is not durable, will split and peel off under anything approaching harsh conditions. Which means a possible fire down the road. The vinyl layer underneath may save you but for no more wire than you are running, don't be penny foolish. Use better insulation.

Your choices? Basically vinyl, SO cords, cross linked, and teflon in order of toughness, durablilty, and cost. Auto manufacturers all went to cross linked in the 90's yet parts suppliers still only stock the old vinyl that was in vogue in the 60's Why can't they move on? Well it's cheap and it's good for a couple of years. SO cords use a heavy rubber insulation and are much more expensive than extension cords but are more flexible and last much longer. But by 40-50 years they may be starting to crack. Cross linked comes in three insulation thicknesses and is available online from places like Del City in convenient lengths and colors. Worth the money. Teflon is hard to work with, usually jacketed in stainless, but pretty much bullet proof. Also expensive, probably more than anything else. Available in 2 and 3 conductor, and various gages.

Then there are the terminations. Don't spend good money on quality wire then expect to just stick the end under a screw head. Buy the adhesive lined heat shrink terminations of the proper size on both the wire end and the lug end and use them.

Finally, if you are running individual wires 1/2" pvc conduit is cheap and easy to work with. It can be bent by softening it in boiling water, using a heat gun, etc, or use metallic conduit. A bender might be $20 and the conduit ends are very cheap. Don't forget the support clips. Once in place you can snake in wires as needed, and distribution boxes make for versatility in runs. Do it right and changing things down the road is a doddle. Also, installing conduit as a late step in the construction is usually pretty easy.

Jim

[richard5933]

Well here we go, that's the other thing. Stranded wire brings an entirely different methodology with it. Definitely safer for vehicles if done right. BUT, don't wire your bus with THHN...
Jim

And then there is this:  https://www.delcity.net/store/Marine-Cable/p_356.h_181036

Flexible, safe, and suited for the conditions found in a bus. Not cheap though. This is the stuff that Custom Coach used to wire all the 120v systems, and it's held up remarkably well over nearly 50 years.