Confused

camprat · 09-25-2010, 02:34 PM

I was part of a posting about 50 amp RV services , But there seems to be confusion in the explanation to help.
I am not doing this posting to put down anyone for trying to help, but would air on the side of causation when giving advice. When Dealing with 120/240 volt. We just don't know what there knowledge or capabilities Are?
This is why, suppose we help with outlet wiring posting 120/240v 50amp.he take all the good advice & starts, but he only has a old rang cable 50amp (ok). It is a three conductor he wire in to his 120/240 outlet And everything is working, but there is no ground he doesn't think about it. This is where the problem lies. He think he got the best of both worlds, trailer power up (120v) & he has 240v/50 amp for a welder or whatever, but the trailer & anything plug in has NO GROUND.
If you have a short to ground in the trailer, it WILL NOT TRIP A BREAKER. And think about this, we all put wooden block under the landing gear. If anyone come in contact with trailer & earth they will be ground. They can lose there life & have.
That is why all plug & outlet have a ground. 240volt is hot-hot-ground, 120/240 volt is hot-hot-neutral-GROUND.
My point is they had the capabilities to get 120/240 volt, but lacked the knowledge to know why the ground was needed.

cfsoistman · 09-25-2010, 04:55 PM

I have no clue what you're attempting to say from your post. So I'm taking a stab at it.
If anyone has a 50 amp service to an RV, requires a 4 conductor wire of #8 Copper. 1-Ground, 1-Neutral and 2-Load wires. This wire actually provides 2-120 volt circuits to the RV. Anyone with a 30 amp service to an RV, requires a 3 conductor wire of #10 Copper. 1-Ground, 1-Neutral and 1-Load wire. This wire provides 1-120 volt circuit to the RV.
In both cases the proper plugs must be used and the wires connected to the correct terminals in the box.
Any other set up is not code compliant and could result in a severe shock or worse.

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Left plug is for 30 amp and the right one is for 50 amp. These type plugs are not interchangeable with 30 amp & 50 amp plugs rated for 240 volts.

NWJeeper · 09-25-2010, 06:58 PM

Well put Charlie. I think many make the mistake in thinking that because a 50 amp circuit for an RV has two 110V cirucits that it makes it 220volts which it doesn't. They are just two 110V circuits in one plug.

The problem comes when those that don't understand this start telling newbies that don't know any better that a 50amp RV should be supplied 220 volts which is completely wrong and dangerous.

jimh · 09-25-2010, 08:20 PM

next time i'm in a campground, i believe i'm going to measure the voltage between the two hot's and see if it is 110 or 220. i know if u adapt it with one of those 50 amp connectors that plugs into 2 seperate sources, u could have it either way.
in the wiring of a house, ur neutral and ground are tied to the same place in the box. (2 hot from the utility and a ground. the ground from the utility goes back to the source and they run a line from it to earth ground usually at each pole. in ur home, u also run a wire to ground from the neutral buss inside ur breaker box).
if u wire ur trailer 220 (110 to ground) and don't connect the ground, it will find a path back somewhere to complete the circuit. this could be u becoming the ground by touching the trailer or u having to complete the circuit thru a piece of equipment tied to the other leg. this is not desirable any mismatch would be dangereous. What u should have inside ur trailer is the neutral and the ground tied to the same neutral buss. the two wires are an insurance and required. the 30 110 plug has a neutral and a ground done the same way.

i didn't see the origional discussion so don't know how much it deviated from what has been posted here. i'm not at all disagreeing with what i'm seeing posted here.

revrnd · 09-25-2010, 08:38 PM

I'm not an electrician, but RV shore power connections seem to be a poorly understood subject. I've even read of situations where electricians have wired 30 amp 220 volt circuits for a home outlet for shore power w/ bad results.

NWJeeper · 09-25-2010, 08:44 PM

Quote:

Originally Posted by revrnd

I'm not an electrician, but RV shore power connections seem to be a poorly understood subject. I've even read of situations where electricians have wired 30 amp 220 volt circuits for a home outlet for shore power w/ bad results.

Abosolutely, it was done by someone here just within this last year with really bad results as you can imagine. My friend also did this on his rig and totally fried the converter/charger. Costly mistake.

jimh · 09-25-2010, 08:58 PM

i believe i just read the post, thats scary. mine has 2 legs just assumed that all 4 prong 50 amp were the same. didn't know that they also made a 50 amp single leg service; i don't believe i've encountered one.

camprat · 09-25-2010, 11:06 PM

CFsoistman made my case in away. he has a good detailed explanation of the 30& 50amp plug. What I was try to get at was us caution when giving advices & taking it in. The example I used to show what can go wrong. IT happen, I was called out to a man house. He to save cost, he wire his old rang outlet through the wall to the out side for his rv & welder to his new 120/240v 50 amp plug. He also put a TV stand on his bedroom wall in the trailer. He ran one of the screws through the hot side of the of the kitchen 20 amp. circuit to the out side skin of the trailer. the next morning he grab the door & 120 volt grab him & he went to the emergency room. The only thing that saved him, he fell. The breaker never tripe. IF he had only had a grounded plug the breaker would have trip when he hit the hot wire.That is why I maybe a pain about get it right & if you can't Don't Do it.

AS for no 240v in rv, it already here in the big special order rig. And it will be coming to your high & mid level rig as a option in the future. We have already max out the 50amp/120v. bigger AC, more Ac, water heater electric fireplaces with heat. IT is come ready or not. That is the only way to cut load 50 amp in half. The new RV parks have already upgrade to the 120/240 50amp services

camprat · 09-25-2010, 11:55 PM

Jimh you are right to say in house main services panel the neutral & grounds are wire the same, But any panel past the service is a sub-panel. This have the the neutral and ground isolated . The ground goes to the metal case of the panel, no jumper to the neutral buss. The rig you plug in to that house is a sub panel. If you look in your trailer panel that is how it wired. this is why if you have a open neutral on your sub feed or panel you don't lose your ground & if you have a hot to ground the breaker will trip. Just a simple explanation .

revrnd if you have a factory wire rig & cord your ok. the problem lies in people miss wiring plug when there change out the plug or miss wire outlet. I have a volt meter that plug in to the 30/15amp x-over & check park voltage and then plug the meter inside the rig to keep a eye on things & this help out dry camping with generator .

railrode · 09-26-2010, 09:22 AM

50 amp rv's are 240 volts (2 hot legs, neutral and ground) 4 wires... Nothing inside the rv uses 240 volts but the panel inside splits it to, 2-120 volt circuits. For example, 1 a/c on one circuit and the 2nd a/c on the other. Each circuit(120 leg) are and should be of a different phase, as 2 (120 legs) of the same phase should not share the same neutral.

A 30 amp rv outlet, 120volts (1 hot leg, neutral and ground) 3 wires, should never have a 2-pole breaker on the main outlet.

NWJeeper · 09-26-2010, 11:08 AM

Quote:

Originally Posted by railrode

50 amp rv's are 240 volts (2 hot legs, neutral and ground) 4 wires... Nothing inside the rv uses 240 volts but the panel inside splits it to, 2-120 volt circuits. For example, 1 a/c on one circuit and the 2nd a/c on the other. Each circuit(120 leg) are and should be of a different phase, as 2 (120 legs) of the same phase should not share the same neutral.

A 30 amp rv outlet, 120volts (1 hot leg, neutral and ground) 3 wires, should never have a 2-pole breaker on the main outlet.

This is true but the danger here becomes when a well meaning individual tells people that a 50amp RV "runs on 240 volts" and the "Conveter/charger runs on 240 volts". This kind of mis-information is what Camprat is trying to get at. This is NOT good information and could cost someone who doesn't know any beter a lot of money or worse start a fire!

For simplicity sake a 50 amp RV runs on two 110volt circuits, leave the whole 240 volt thing out of the equasion lest some confused individual asks a moron electrician to wire his RV receptacle for 240 volts!

Again, it has happend with disaterous results.

johnnyjoe · 09-26-2010, 12:02 PM

Camprat, I believe you are stressing the importance of proper grounding. Grounding provides a path for electricity to follow back to its source in the event of a fault. If that path is not installed, you could become that path with fatal results. 600 people are electricuted in the US each year due to bad electrical installations and ignorance about electrical wiring. One more tip for you all, circuit breakers protect equipment, GFCI's protect you.

camprat · 09-26-2010, 01:23 PM

Thank you, all I wanted to do was to get people to thinking about what there doing! When giving advice & taking it. You can replace THINGS, but can you replace your kids or yourself.

Boyd · 09-26-2010, 02:06 PM

I've been doing my own wiring for many years and thought I knew enough to keep myself safe. Because of the great information supplied in this thread, I may even last a few more years. Too soon old and too late smart.

jimh · 09-26-2010, 09:48 PM

Quote:

Originally Posted by camprat

Jimh you are right to say in house main services panel the neutral & grounds are wire the same, But any panel past the service is a sub-panel. This have the the neutral and ground isolated . The ground goes to the metal case of the panel, no jumper to the neutral buss. The rig you plug in to that house is a sub panel. If you look in your trailer panel that is how it wired. this is why if you have a open neutral on your sub feed or panel you don't lose your ground & if you have a hot to ground the breaker will trip. Just a simple explanation .

revrnd if you have a factory wire rig & cord your ok. the problem lies in people miss wiring plug when there change out the plug or miss wire outlet. I have a volt meter that plug in to the 30/15amp x-over & check park voltage and then plug the meter inside the rig to keep a eye on things & this help out dry camping with generator .

the cob webs are starting to disappear...i remember abt the sub panel having to be connected to the main panel.
i remember the one thing the inspector didn't want to see was the earth ground going into the meter base. we had to run it up and conect it to the main panel. don't remember if that was to the housing or ground bus but suspect it was the housing...

i've been giving a lot of thought to putting a 220 dryer circuit in the trailer. so far what has stopped me is some of the campgrounds don't offer 50amp and i sometimes tie to two circuits and doubt that it is 220...two 30 may = 60 amps but not the same as 50 amp 220. if i ever decided to do something like this, i would do a lot of research first.

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