How to run wires in a bus (order of operation)?

[Sleddgracer]

Originally Posted by Brewerbob

Mythbusters did an episode of peeing on the third rail. I'm not trying it but I think they went with busted on it killing you.

for instance, spray from a pressure washer blowing across high voltage lines will not arc or conduct electricity as a lineman testified at my WCB hearing - water was normal tap water

[Taz420]

Originally Posted by Brewerbob

Ok so arc is the wrong word. A wet leaf across the terminals will have the same result as arching tho. A blown breaker and/or cooked wires.

No, a wet leaf is technically a resistor. It's not a short. It will cook the leaf until there's no water left, and that'd be it. It might melt something from the heat transfer through the metal, but it won't be enough to trip the breaker. That's the whole principle behind the AFCI (no I won't get into the debate whether they actually deserve mandate into NEC). An arc can create enough heat to cause a fire without drawing enough current to trip a breaker.

Originally Posted by Brewerbob

How about that... wiki says 33kv/cm. A different wiki page says 3k/mm which is 30k/vm. Guess I need to read the data plate on the back of my neon transformer.

It's probably 10kV or so. But the whole thing with a Jacob's Ladder is that the electrodes are in a V shape, with the bottom only a few millimeters apart. Once the arc strikes, it can run up the widening gap thanks to ionization of the air around the arc (plasma is far more conductive than air). Ever see videos of transmission station circuit breakers opening? Some of those arcs go 20-30 feet wide with 345kV. Sometimes you can even get a sustained arc on a regular power pole when a 15kV explosive primary fuse fires.

Originally Posted by Brewerbob

Mythbusters did an episode of peeing on the third rail. I'm not trying it but I think they went with busted on it killing you.

It was busted due to the average person not being capable of producing a laminar (electrically solid) stream of urine long enough to connect the body with the 3rd rail on the ground. It breaks up into droplets within a few inches of leaving the body. They did prove that urine will conduct lethal current over at least 6 feet at 600V (using a fluorescent ballast). They revisited it a few years later and Adam did get shocked by peeing on an electric fence.

[wireguy]

I am starting the installation of electrical and plumbing in my bus. I am a master electrician specializing in service work so these kinds of projects is what I spent my career doing. My basic position from the get go is I want all my utilities accessible. It is entirely possible you will get down the road a bit after your installation and realize you badly want to change something, or need to make a repair. If it is all encased you will regret doing it that way.
As to the electric, ampacities are based on the heat generated in the wires being able to shed that heat. Wiring embeded in foam will never get to shed heat. This will result in two things. One, your wire insulation will break down comparatively quickly. Two, there are two components in a circuit breaker. Thermal and magnetic. If your wires never get to shed heat that heat will be transferred into the circuit breaker and the thermal will trip the breaker out way more often than it would if the wires could shed heat. Of course then the temptation will be to go up a size on your circuit breaker. In addition to being very illegal this will fry the insulation off your wires pretty quickly.

I am running 3/4 pipe down low on the wall on the driver's side because that side feeds the two roof mount air conditioners and the refer as well as outlets. Only outlets on the passenger side so 1/2" EMT on that side. I am using 4 square boxes surface mounted everywhere because there is lots of room in them and you can cheaply buy 4 square raised "industrial" covers in pretty much any configuration you could need. I am fastening the conduit on Minerelac "stand off" straps so the pipe (EMT) will be centered on a pre existing rib down there that runs the length of the bus.
It is legal to run 12 volts in a 120 volt system as long as the 12 volt wires are rated for the highest voltage the AC system will use. In practical terms this means THHN/THWN solid building wire which is a lot cheaper than buying automotive type wire for your low voltage. I use 12 and 10 stranded a lot. That wire is all rated for 600 volts.

I am a function over form guy and I know that every system will need work sooner or later so I want everything accessible.

[synestine]

Originally Posted by Brewerbob

Mythbusters did an episode of peeing on the third rail. I'm not trying it but I think they went with busted on it killing you.

It doesn't kill you because the "stream" breaks up within a handful of inches after leaving the body. Get within that distance and it tripped their sensors.

[Dirtdoctor]

Run wiring and water in conduit and waterlines. I don’t like pex but some swear it’s the best. Foam after elect and water and cat 5 cables and any other interior stuff is connected- then spray foAnd siding. It will be a quiet ride with that insulation. Then trim out like a regular home.
Cheers

[Brewerbob]

Originally Posted by wireguy

I am starting the installation of electrical ...


I am a function over form guy and I know that every system will need work sooner or later so I want everything accessible.

I like this.
Navy ships have EVERYTHING exposed. Looks like a$$ but serves a function. Nowhere near as many runs on a skoolie. I think I'm foaming first. Only exception being windows. I think I'll buy those and get them installed, masked off, and then foam. I should probably get a move on it since we are already more than a week deep into Aug. Gf's daughter is getting married in Oct so life is going to get in the way and it'll be cool/cold weather sooner than I'm ready for it. Paint and foam wise. I'm ready for cooler weather for myself NOW.

[Brewerbob]

Originally Posted by Dirtdoctor

Run wiring and water in conduit and waterlines. I don’t like pex but some swear it’s the best. Foam after elect and water and cat 5 cables and any other interior stuff is connected- then spray foAnd siding. It will be a quiet ride with that insulation. Then trim out like a regular home.
Cheers

I dunno if I trust the crimps on pex but they say it works and it's what I'm going to use so time will tell.

So you're saying to insulate it all in place but inside conduit?

[Taz420]

Originally Posted by Brewerbob

I dunno if I trust the crimps on pex but they say it works and it's what I'm going to use so time will tell.

So you're saying to insulate it all in place but inside conduit?

PEX crimps work just fine, as long as you use the proper crimping tool (which you can usually rent for a few bucks at an Ace or Do It Right. They ratchet down and will not release until the ring is at the proper size. There's really no way to screw it up.