120V Wiring Help Needed

Highway Yacht · May 14, 2011, 02:22:14 PM

I'm at the house wiring stage now and I'm sorta lost. So now I need some help. I'm wanting to do a 50 amp service. What I need help with is wiring from the breakers throughout the Coach. I know my travel trailer uses a #10 wire for the A/C's and #12 wire for most everything else. I'm not sure about the water heater but I would guess that is also a #12 wire. The travel trailer uses a romex looking wire with 3 wires inside. The colors are Black, White, and a non insulated copper wire. Can I also use this type of Romex in my Coach?? If so, would the insulated copper wire be connected to the common ground bus or the neutral ground bus?? My thinking is the Black wire would be hot, white would be common neutral, and the non insulated copper would be common ground but I want to make sure.
Also, is it common practice to wire all of the outlets and appliances with 20 amp breakers and #12 wire and only the A/C/s with 30 amp breakers and #10 wire?? I can't think of anything I will have in the coach that will draw a lot of amps other than the A/C's. The stove and oven are propane, the water heater is electric/propane, the fridge is a 3 way. I will install a couple electric space heater that I plan to tie into the 30 amp A/C breakers since the heaters and A/C's will never be used at the same time. I'm sure I'll have more questions about the wiring as I get deeper into it. Any help would be greatly appreciated.

Jimmy

happycamperbrat · May 14, 2011, 02:39:52 PM

Quote from: Highway Yacht on May 14, 2011, 02:22:14 PM
Any help would be greatly appreciated.

Jimmy

haha!! You want "my" help? lol

The only thing I can tell you is that Ace taught me to put the back side of my finger to anything I thought "might' be hot...... this is confirmed to be an old electrition's trick to avoid getting the shock of your life!

bevans6 · May 14, 2011, 03:13:00 PM

commonly you wire all the outlets except the AC with 14 gauge wire and 15 amp breakers. The AC gets a dedicated 20 amp breaker and 12 gauge wire. Nothing gets a 30 amp breaker and 10 gauge wire unless you have an odd-ball appliance like a 120 volt clothes dryer or something similar.

While the bigger is better thing might work on a beach or in a locker room, I can think of no reason to wire normal outlets for anything more than 15 amps. You need to get different outlets, you pay way more for wire, it's not needed and it's a waste. Same with the AC feed. Just about any AC unit that needs more than 20 amps at 120 volts is going to be a 15 amp 240 volt unit. Not much commonly installed in a bus needs 30 amps at 120 volts.

Brian

Brassman · May 14, 2011, 03:35:28 PM

I have a 6 gal electric water heater with a 2000 watt heating element. The manufacturer recommends 10 gauge wire and a 25 amp breaker. I would say install the bigger wire if in doubt, because, in a coach, with it's relatively short wire runs, the added cost is minimal compared to a redo to put in larger wire, if needed.

Chopper Scott · May 14, 2011, 03:49:04 PM

Here's a link that you might find some info from Jimmy. http://dasplace.net/RVWiring/wiring.html Iknow it doesn't answer your wire size question but it covers the basics.

papatony · May 14, 2011, 05:41:02 PM

Hway I used a 30 amp and 10 wire for ac's ,12& 14 for every thing else with 20 amp breakers that is over kill I know but I would father be over than not enough

Sean · May 14, 2011, 08:25:18 PM

Quote from: papatony on May 14, 2011, 05:41:02 PM
Hway I used a 30 amp and 10 wire for ac's ,12& 14 for every thing else with 20 amp breakers that is over kill I know but I would father be over than not enough

That kind of thinking can lead to real trouble.

You should never use a breaker larger than the size recommended by the appliance manufacturer. If your A/C manufacturer specifies a 20-amp breaker, using a 30-amp one instead can damage the air conditioner, possibly irreparably. The manufacturer is relying on that breaker to cut off the current in a locked-rotor situation; oversizing the breaker can literally burn up the motor.

Even if the motor itself is undamaged, you are risking a fire. That's because the manufacturer uses wiring rated only for the specified load; while the #10 wire you ran for the branch circuit can handle 30-amps, the #14 wire inside the unit can not. If your unit is having issues that cause it to draw more than the rated current, these wires can ignite.

I suggest you replace your 30-amp breakers with ones rated per manufacturers' specifications.

-Sean
http://OurOdyssey.BlogSpot.com

mikke60 · May 15, 2011, 02:54:25 AM

Thanks Sean. you could not be more right. Over sized breakers are a sure recipe for trouble. I also could not agree more with folllowing the specs that come with each device. They are there for a reason.

Highway Yacht · May 15, 2011, 04:15:36 AM

Thanks for all of the advice so far.. Does anyone know if I can use the romex wire with the non-insulated copper wire as my common ground "green" wire? It does have the black and white wire that are insulated but the center ground wire itself is not insulated seperately once you cut off the outer insulation. It looks identical to the wiring in my travel trailer.

Jimmy

Sean · May 15, 2011, 05:41:57 AM

Quote from: Highway Yacht on May 15, 2011, 04:15:36 AM
.. Does anyone know if I can use the romex wire with the non-insulated copper wire as my common ground "green" wire? It does have the black and white wire that are insulated but the center ground wire itself is not insulated seperately once you cut off the outer insulation....

Yes, type NM cable, often known by Southwire's trademark "Romex^®", is acceptable and commonly used for 120v house wiring in a coach, so long as it is installed with the proper fittings and is properly protected and secured.

-Sean
http://OurOdyssey.BlogSpot.com

David Anderson · May 15, 2011, 06:32:25 AM

Sean,

How did you make the trademard registered symbol after the typed Romex word?

David

Sean · May 15, 2011, 07:00:05 AM

Quote from: David Anderson on May 15, 2011, 06:32:25 AM
How did you make the trademard registered symbol after the typed Romex word?

I just chose it from the Windows character map and pasted it in. I do the same to get the degree symbol or other special symbols.

Go to Start -> Run and type "charmap" in the box, then hit enter. Or Start -> All Programs -> Accessories -> System Tools -> Character Map. Select the symbol you want, press "Select" then "Copy" and paste it as usual into your message.

-Sean
http://OurOdyssey.BlogSpot.com

MEverard · May 15, 2011, 07:02:58 AM

Highway,

You can also use MC Cable which is the same wire but it comes in the flexible aluminum jacket. It is nice because it protects the wire in exposed places from damage. I am glad to see Sean pipe in about the breakers and wire size. A breaker is there for a reason, and oversizing is a recipe for disaster. Something you might want to consider is to put in a couple of future raceways. They make the flexible tubing that you can install in some walls for future wiring that you may want but have neglected to include before closing up your walls.

Good Luck,
Mike

Len Silva · May 15, 2011, 07:49:49 AM

You can also use the "alt codes" in the character map. For instance pressing ALT and 0174 on the number pad will give you ®, ALT-0169 for ©.

http://tlt.its.psu.edu/suggestions/international/accents/codealt.html

TomC · May 15, 2011, 08:06:43 AM

Wiring the bus for 120vac is relatively easy. The important part is to get the grounding wiring correct. Basically, when you're running the generator, you want the grounding to go to the generator and to be bridged with the negative. When on shore power you want the generator bridging to be inactivated and only be grounded the normal way through the power cord. If you have an inverter, they typically do this automatically. If I got this wrong-I'm sure Sean will correct me. Good Luck, TomC