Breaker Box Installation Questions

[soused moose]

I just started laying in our 120 wiring lines and have a question for you Bus Converters.

Did you Install your Breaker Box set-up yourself ...or did you have an electrician do it ?



If you did it yourself ...was it pretty simple and easy to understand ?



On our Last Bus conversion 'Home' , I paid an electrican to hook up the Breaker Box . But , I'm feeling braver with our new Bus, and am tempted to do it myself.

Any pointers you could give me would be a great help.

Thanks, Michael & Millie

[Les Lampman]

Michael,



If you did the rest of the bus...all the wiring, the outlets, the swtiches and such...you've done the hard part; the breaker box is easy and no more difficult than any other part of the system. If you've been wiring up outlets and such you know you have to "switch gears" from thinking about 12-volt color-coding when going to the 120-volt system (black is NOT ground!); when you work on the 120-volt system make sure and keep reminding yourself of that. As long as you get the hot, neutral and ground wires to the right places on the breaker box (they should be labeled and the box usually has instructions) it's a very simple process; just do one circuit at at time (make all three connections, then move to the next circuit) and then bring the main feed into the box and connect it...voila! Really, it's just as easy as the 12-volt system.

[Les Lampman]

Michael,



Maybe I should have been a little more specific...



Let me compare it to the 12v DC wiring; in the DC system you've (usually) got the (+12v) 'bus' bar feeding all the fuses (or circuit breakers) and another 'bus' bar for all the grounds. From each fuse (or circuit breaker) you'll have a 'power' wire (usually red) running to each load and then a 'ground' wire (usually black) back to the ground bus bar. Then the power (+12v) bus bar and the gound (-12v) bus bars are each connected to their respective battery terminals for power. There should be an in-line fuse or circuit breaker in the main wire that feeds the +12v bus bar (as close to the battery as possible) to protect the wire that runs to the positive bus bar in case of a problem. [With a metal body the 'ground' side might be the body or chassis; obvioulsy this would be a really BAD thing with 120-volts!]



[This follow desription is from a physical 'wiring' perspective only; not from an electrcial theory perspective. The intent here is to get the system wired and things working.]



In the 120-volt breaker box you'll have the same set up really; a black 'hot' wire going from the circuit breaker to the loads (this is equivalent to the red +12v wire in the DC system), the white 'neutral' wire going to a common bus bar (this is equivalent to the black (-12v) wire in a DC system from a wiring perspective). Then you'll have the green (or bare) 'ground' wire which goes to a common bus bar.



The main feed (shore power) cable gets wired into the box the same way...that is, the black 'hot' wire is connected to the hot bus that feeds all the breakers, the white 'neutral' wire is connected to the neutral bus and the green (or bare) 'ground' wire is connected to the ground bus. Just make absolutely certain that the plug on the end of the shore power cable is correctly wired (if it's factroy pre-assembled that won't be an issue); when you plug into shore power you want to know that ground really is ground and that the polarity isn't reversed (that's where the nuetral wire is 'hot' and the black becomes the 'neutral'). The bottom line is just make sure every thing is connected color-to-color and that the shore power plug is absolutely, positively wired correctly and things will work great.



There's a good schematic from Ample Power here.

[Steve]

If I understand it correctly. The only reason it matters if the hot and neutral wires are correctly connected is because you don't your appliances out of phase. It shouldn't matter if the shore power is wired correctly as long as everything INSIDE the bus is wired the same way. It is the same danger that if you are using your inverter or generator you will be out of phase from the shore power and if you were to use those sources together you would be in a very bad position.

[Les Lampman]

Hi Steve,



That's not totally correct. If you've wired the inside of your skoolie correctly (color code wise) and then connect up to a shore power receptacle that's wired 'backwards' you're feeding the 'hot' side of the 120-volt power to the wrong side of the circuit and therefore when you trip the breaker the circuit in the bus is just 'open' and not de-energized; any failure in the circuit's wiring will complete the circuit with potentially bad results. The same thing would happen if you wired the shore power plug 'backwards' (unless all the internal wiring was consistently backwards too; in which case you've just reversed the meaning of the hot and neutral color coding and haven't change the physical characteristics of the circuits).



With the breaker closed and the circuit energized appliances with on/off swtiches are seeing power on the 'wrong' side of the switch; that means all the wiring in the appliance is 'hot' and only the switch is keeping it from operating (in a correctly wired system the appliance wiring doesn't 'see' the power until the swtich is closed; an internal wiring failure would not create a problem until the on/off swtich were closed). If there is a failure in the internal wiring the potential is high for someone to receive a shock even with the appliance turned 'off' since everything inside is 'live'.

[soused moose]

Thanks for all your help here Les

It's a big help for us, Michael & Millie

[lapeer20m]

I don't think my bus is not up to NEC (national electric code) standards. All power coming into the bus runs through a GFCI, except the power going to the jacuzzi. I have three alternatives as far as power sources are concerned. Shore power, generator, or inverter. Only one of them can be hooked up at a time or else bad things happen. When it comes to electronics, once the "magic smoke" escapes, you can never put it back in!



To get power to the bus, everyting runs off of one circuit. There's just not much of a load. Small frige, tv, vcr and a couple recepticles. Power gets to the circuit through a standard male plug. I have three standard outlets: one wired to each of my power sources. I simply plug the male plug into the outlet that i want to use ie: geni, inverter, or shore power. This way there is no possibility of connecting two power sources together and causing the magic smoke to escape.



I excell at 12v circuits, but i know almost nothing about house current. The Ground wire for my 120v system is not used at all. There was a rumor i read somewhere that said the GFCI woulnd't work if there wasn't a ground wire, but this info is false. I asked a certified electrician, and i physically tested it myself. One thing i'm not sure of is what happens if a wire abraids, and touches the bus chassis......i suppose if tied into shore power a person standing on teh ground could get a poke ???? I don't really know.

[Steve]

I don't have a breaker box in my either. I usually don't use shore power but when I do I guess I will rely on the breaker for the shore power. Most of the time I run on the inverter and that has a built in breaker also. I guess I don't really see the point in having several circuits in the bus.

[Les Lampman]

Hi Steve,



I totally agree; just put in what you need.



For the purpose of discussion I'll continue...



Here's one reason someone might want multiple circuits...let's assume 30-amp shore power that we're plugged into and go from there.



So in the morning we decide to crank up the coffee maker and while we're at it we want to run the microwave. [I know, assuming you've even got this stuff but it's just an example .] We'll assume the coffee maker is 900 watts and the micro is 1200 watts; that's about 8 amps for the coffee machine and 11 amps for the micro and we're well within the 30 amps we have available from shore power. However, we're well above the 15 amps that a single branch circuit carries if the outlets the coffee maker and micro are plugged into are 'daisey-chained' on the same circuit. If we had two circuits (each at 15 amps) we could fully utilize the 30 amps that shore power can supply. Getting 30 amps off of one circuit takes some pretty hefty wire if it's got any distance to travel (look at the size of the typical shorepower cable!).



Another reason for multiple circuits is control; you can shut power down to selected outlets, switches or equipment (like the water heater) and not take down the whole system. And if you only have one circuit and trip the main shore power breaker you lose all power instead of just power on a branch circuit.



I feel more comfortable protecting the wiring in the bus with it's own breaker and each circuit with its own breaker too. That way problems stay isolated to small sections of the system and don't affect the whole shebang. And problems stay smaller in that a problem on a branch circuit trips the branch breaker much more quickly than it would the main breaker on the shore power supply. If fact, the shore power supply breaker could very well be 50 amps (and we've used an adpater to connect our 30 amp shore power cable) and everything in the bus could experience a melt down before the 50 amp breaker tripped (especially since it's doubtful our bus wiring has been designed to handle 50 amps, which a direct short could develop in a heartbeat).



And that brings up my final point, you don't always get 110/115/120 volts at the shore power supply; that depends on how good the wiring and power is to the supply. I've seen voltage below 100-volts in some locations and that means you're going to draw more amperage and subject your system to higher loads. Watts = voltage times amperage in AC or DC systems; your loads always require the same wattage to get their job done (i.e. - a 60-watt light bulb always needs 60-watts regardless of the voltage) so as the voltage drops the amperage has to go up to keep the equation in balance. On really low voltage big loads like a micro can really draw a lot; in fact we can develop our own mini 'brown-out"!



The cool thing about Skoolie conversions is that we can make them whatever we want them to be. That means different strokes for different folks and no one thing works for all folks. I'm not implying (at all) that every bus should have an AC system like I've described but if you decide to do a full-on AC system it's nice to have some info available to draw from and that's what I'm attempting to provide here; I hope it helps.

[Vern1]

Greetings,

One thing to consider: another reason why the white neutral and ground are seperate(in RVs) is because of generators.

A lot of generators will smoke if you have the hard ground and neutral tied together. I think Onan is one of the ones that you have to have the neutral and ground seperate or they will short out.

You can also never be sure how the shore power is hooked up like said above.

There is a simple led device that you can plug into a shore power plug BEFORE you plug in your bus that will let you know if it has hot/neutral reversed.

[Vern1]

Greetings,

Just got my copy of NFPA 70.

It states that the ground shall be grounded.

The white shall be neutral (i.e. floating and not grounded to chassis) EXCEPT when hooked up to shore power and the ground to neutral will take place at the shore power box, not on the RV.

[lapeer20m]

i leaned something from a person at radio shack once.



we were discussing hooking up a cb radio backwayds, and the lady behind he counter said to me



"once the magic smoke escapes, you can never put it back inside"

[busone]

From what I have read and always heard you want a floating neutral as previously posted. The ground is grounded to the bus chassis and the neutral is compelety seperate. Otherwise there is the chance somebody will get a shock. As I understand it you would want to use a secondary type panel that has seperate ground a neutral bus bars. With a main panel the two are bonded together. I think when the time comes I am also going to use an AFCI breaker just in case a wire gets worn on a sharp edge. I also plan to use BX or PVC conduit to protect the wiring. What is everybody doing when connecting wires, are you all using wire nuts or soldering? I worry about wire nuts coming loose from vibration? It is great to be here on the new and much better group. I hated posting on the yahoo group for fear of getting bitched at.

[Steve]

This is what was posted as the 120V wiring code:

From Article 551, Section 54

a. Power Supply Ground wire(bare copper, green or green w/yellow

stripe) shall be grounded(bonded is the term they use) to hard

chassis ground. Microwaves, Coffee Pots, LP Pipes and water pipes(if

metal) shall also be bonded to this ground.

b. Your Distribution Panel(breaker box) shall have enough terminals to

attatch said ground wires.

c. Insulated Neutral

1. Your neutral(white wire) shall be insualted from hard chassis

ground. It will be a floating neutral. This is not tied to

appliances, frame, LP pipes, etc. THE ONLY TIME IT IS TIED TO HARD

GROUND IS WHEN YOU ARE PLUGGED INTO A PROPERLY WIRED SHORE POWER PLUG.

2. Appliances that are plugged into sockets in the RV(240V stuff

here) are to be connected with a 3 pole, 4 wire grounding type plug

and receptacles.



Basically, the ground wire is grounded.

If the hot rubs against the frame or ANYTHING metal, the onboard RV

breaker throws.

If the shore power neutral/hot is reversed, since the neutral is

floating, you don't get zapped when you grab the bus frame while

standing on the ground. It will throw the shore power breaker if it

shorts to frame/chassis/ground and since it is floating, little Fee

Fee that is chained to the bumper won't be doing a mystical doggie

dance.

[busone]

That is just what I was thinking, it is always good to hear somebody else say it in such clairity. I tend to make something simple sound complicated.

[Les Lampman]

Hi busone,



You asked about wire nuts and solder for your wiring connections and the answer to this requires that I make a statement about the wire itself. Please understand that it is decidedly not my intention to find fault with the way anyone else has chosen to wire up his/her bus. My comments are based on my background as a marine electrician involved in wiring for harsh (and moving) environments. If you used something else in your bus don't flame me ; this is just my viewpoint.



In my opinion you should consider not using solid copper wire for your AC system; for all marine applications stranded wire (and tinned in saltwater environs) is called for because it can withstand the constant motion and vibration of a moving vessel and solid copper tends to work harden and become brittle...and then break. It's also why all the 12-volt wiring in your car is stranded; that and the ease of routing stranded wire. Using stranded wire also makes it possible to crimp your connections (use a good double crimper); this is not only easier but has been found to hold up much better than soldered joints in moving vehicles and vessels. You might be interested to know that it's just about the only type of electrical connection made in aircraft and their needs are much more critical than ours.



A good solder joint is fine (except for vibration breaking it apart) but it's not necessisarily an easy thing to do without experience and it's very difficult to visually tell whether a solder joint has been done well or not.



It's certainly possible to do poor crimp connections but if you buy quality connectors (check out Terminal Town on-line) and use a good double crimper (the second crimp grabs the wire and provides strain relief) good results are easily obtained and quite repeatable.

[IWC Bus]

Good Morning All;

I have read the thread on Breaker Box Installation Questions. Well I am not quite grasping the whole concept yet, I am almost there!

Well the Black wire is the hot wire and should be wired into the circuit breaker. The white wire is the neutral wire and should be wired into the neutral bus. Finally, the Green or bare wire which is the ground wire needs to go to a Grounding Bar?

I purchased an Eaton 125 Amp 4-Space 8-Circuit Flush Cover Indoor Type BR Main Lug Load Center from the orange box store and there is only one (1) bar in the box in the upper right corner. Do I need to purchase another box like Eaton GBK14P Cutler Hammer Ground Bar Kit-GROUND BAR Kit? And connect that ground bar to the buses chassis?

I have wired all the 120v receptacles in placed, tested them with an Power Gear 3-Wire Receptacle Tester and I about to rewire the 12v lighting using the bus’s preexisting 12v lighting with an upgrade to LED bulbs.

I want to get this part down pat before I even think about the Solar panels, 50-amp shore line, and generator.

So Skoolie Forum member with the no how hit me back. I am hoping that Les Lampman is still on the forum because I saw that his background is in marine electrical.

[Rusty]

...a 13 year-old thread? They were delivering my bus new when he wrote that last post.

Grounding is a tricky subject when discussing RV. Green is ground, yes and the screws will be painted green on receptacles, etc.

Make sure you design the complete RV elec system, I don't want you to have to go back and redo a section. Post your diagrams. get an electrician to check your work.

discussion

good source

https://www.youtube.com/watch?v=yMeNcRGVcUE