BAC Forum
General Boards => Technical Support => Topic started by: Chris Hempel on September 03, 2020, 02:31:04 AM
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Does anyone have experience with using your in house electric dryer connection for shore power. Home Depot makes a conversion cable that makes this possible- dryer three Prong to RV four prong. Would be convenient for us to be able to run one AC unit while loading up for a trip.
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Chris, I would be surprised if your dryer is wired as a 110v 3-wire circuit. Have an electrician come out and determine how your dryer is wired. Most dryers are 220v 4-wire.
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And one other tip: RV 30A blade type extension cords can burn up pretty quickly when running one A/C. Watch the head of the cord for overheating (where the blade type connection is). I have cords with burned blade ends, my run was about 100' to the 5th wheel (our previous RV). I have changed all my blade type 30a cord ends to twist lock connections-no more high resistance blade type connections
https://www.homedepot.com/p/Legrand-Pass-Seymour-Turnlok-30-Amp-125-Volt-NEMA-L5-30P-Locking-Plug-L530PCCV3/100166915
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I considered doing the same thing until I found that my dryer outlet was missing a neutral so I just had a 50 amp outlet added.
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The 3 wire dryer outlets normally have 2 hots and a neutral. No ground.
Steve
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My dryer is for sure 30 amp 220.
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Hopefully this will better display the HD page.
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Steve - That's what I was thinking. A house clothes dryer plug is actually a 240-volt receptacle - two 120-volt hot wires of opposite phase so that between them you get 240 volts and one ground/neutral; therefore, three prongs. Using a house dryer receptacle to power your RV looks like something that is do-able but you better know what you're doing or get an electrician to do it.
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Chris, usually you can convert a 3 wire dryer receptacle to a 4 wire because their is a separate ground wire in the outlet box.
You would have to change the cord to the dryer to use the dryer, it is a much safer connection than a 3 wire connect and is now no allowed in the National Electrical Code.
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If your coach has a Surge Guard protected transfer switch, one that looks for open neutral, open ground, etc, it may not allow the hookup as you will not have a neutral with your 3 wire connection. i have an outside 3 wire, 120v RV receptacle that I wired straight off my house breaker panel and I can run one A/C in the MH that way. It has one hot, one neutral and one ground. Standard Rv 30a receptacle.
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Bll is correct
if your drier receptical has three terminals only it is only capable of 240 volts the three terminals are 1) leg 1 or phase 1 and leg to or phase 2 between there is a potential of 240 volts. The third terminal is a ground or bond wire this is supplied to the appliance to ground the chassis of the appliance in case of an electrical failure in the appliance (ie. a situation where the appliance could have power connected to the body of the appliance creating a shock hazard)
If this where to happen the grounded or bonded chassis of the appliance now completes the circuit back to ground at the panel effectively shorting the circuit and tripping the circuit breaker .
Every circuit by code must be set up this way to make them fail safe.
In the three wire circuit there is no common wire (white ) to allow for a split phase as per say so you can only get 240 volts from the circuit which is not what you need for your coach ( bad things happen when you remove the common wire from the equation )
Now with that said some people use a hack where they rewire the receptical to use the ground wire as both the common and the ground the problem is that this circumvents the redundancy of the two return wires and is not legal .
In a coach or even your house for for that matter if you loose your common connection to the coach or house at the breaker panel because all circuits share the same common buss bar when that common is no longer connected the two phases are connected together through the now isolated common buss bar and now the circuits have a total potential of 240 volts instead of 120 because of the back feed created by loads on each of the phases things like tv s and radios etc don't like to be fed 240 volts( see what I mean bad things happen with out that redundant ground circuit) if the ground is still intact it now will take over as common because in the breaker box the two are anchored to the box . This is another reason for the redundant ground or bond wire.
The truth is the only difference between the common and the ground is the common goes back to the power pole and the transformer and grid where as the ground goes out from the panel to a ground rod outside your house buried in the ground and there is another ground rod at the foot of the power pole buried hence the name ground as it actually uses the ground as a conductor.
In a true slit phase receptical there are three wires a red we will call L1 a black we will call L 2 a white known as a common and a green or bare copper wire known as a ground or bond wire
In this arrangement you have 240 between the red and the black
You have 120 between the red and the white
You have 120 between the black and white
And the green is used as a redundant ground to bond all metal parts in the system such as electrical boxes conduits and even the alliances.
It is important on a coach that the ground or bond wire be functional because in the event there was a problem with wiring or a faulty appliance without the ground or bond wire there is a possibility that the coach frame could be powered ( hot) and as the coach sits on rubber no one is any the wiser untill they step out say with one foot on the entry door steel step and the other foot on that nice dewy grass ground and a shocking hazard takes place .
This is especially a problem on metal sided coaches or trailers like the air stream trailers .
Sorry for going on for ever
Hope this helps
Eric
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I was a little confused over this thread, I guess because I didn’t realize there ever was such a modern appliance with no ground, esp. 240v. Ouch. Using a ground and a neutral as one didn’t sound palatable. Greg’s and others’ contributions make sense after I read the article below.
https://www.thespruce.com/change-dryer-cord-3-prong-to-4-1152248
If it were me I’d upgrade my outlet and my dryer cord to 4-prong. Safer all around. Or like myself and others here, have an electrician install a 30 amp RV outlet on the house near the coach.
Joel
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First of all, thanks for chiming in guys. I value your inputs.
Secondly, maybe it would help to know what equipment I have. I don’t know how to put it in my profile.
40’ 2006 Beaver Monterey Laguna IV
Four slides
400hp Cat C9
Pulling a 2017 Chevy Equinox
So between Eric’s post and a conversation with a Master electrician friend I’m still unclear as to why or why not this pigtail from HD will work for me. Is there any reason to believe my dryer connection (except for pin configuration) is any different than an RV park 30A plug-in. Don’t we all have that conversion pigtail on hand so we can plug our big rig in at a park that only has 30 amp capability?
If you look at the attached Home Depot page you’ll see that this pigtail actually has a 14ga ground wire coming off the four pin connector that you plug into the earth ground lug on any standard 110 wall socket. Would this not give me the redundancy Eric talks about? It even mentions RV 50 amp on the listing.
Don’t get me wrong. I am paying attention to what y’all are telling me, I just really want to do this so am trying to make my case.
What you think?
And thanks again.
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The dryer plug is kind of a cross between an RV 30-amp plug and an RV 50-amp plug... with three wires like the 30-amp plug but offers 240 volts like the RV 50-amp plug. For an RV application, that fourth wire is needed to ground the RV and its electrical components.
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If you don't mind your coach electrical items getting smoked and maybe a fire? Why not go to your breaker panel and have a 14-50 am box and breakers wired in and be done with it. If your coach cord will not reach get a extension 50 amp cord it will cost you a bit of money but now your not worried about charging your coach with 240 volts and paying to replace a lot of expensive items.
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“ Is there any reason to believe my dryer connection (except for pin configuration) is any different than an RV park 30A plug-in.“
Chris, obviously the power box in a park will have a dedicated ground. Your 3-prong dryer setup does not. Since the pigtail includes a way to connect its 50amp female end’s ground directly to your house ground, I would expect that to protect you, assuming everything in the house distribution box connects to a common ground buss. But I’m no electrician. I’m not sure why you were left unclear on this after putting it to your electrician friend. Run it by him again?
Joel
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We all have a "friend" who knows something about electricity. Well intention friends are always willing to help us out and make suggestions to meet our needs. This is why have NEC (National electrical code) It is the standard by which all electrical stuff is established. Coaches above all need an established ground because they are sitting on rubber.
One of my favorite conversations with a new RV owner with a 30 amp service went like this: He brings it back to me after owning it for 2 weeks and says "there is something wrong with the electrical in this coach" Nothing works any more after I plug it in at the campground. No air conditioner, tv's microwave, refrigerator, ect. This coach is junk. Doesn't the manufacturer and the Dealer check these coaches out before they sell them! I reply "of course we check them sir before we deliver them. I ask "did you plug your coach in at your house?" He says yes as a matter of fact I did. I ask "where did you plug the power cord into it". He proceeds to tell me how his neighbor advised him that his electric dryer in the garage has a plug similar to his RV power cord plug. I ask him "what did you say after he told you that" He said "can you help me make an extension cord so I can reach the motor home out in front of my house. Then I asked "what happened next". He states "we made the extension cord because it was easy and Home Depot had the plugs we needed. Early the next morning we plugged the coach in and then loaded it with our belongings and food at set out for our first adventure. When we got to the campground nothing worked. So here I am and what are you going to do about it! I reply "You better call your insurance company and ask them"
Moral to this story is "don't do a Rube Goldberg modification to your Coach. Please comply with all appropriate electrical standards and your coach will provide great memories. Thanks, Fred
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Fred has it spot on. Plan and simple a dryer plug is wired 240 volt, your coach lives on 120 volt, if you feed it 240 volts just call your insurance company and explain to them what you did.
Don't mess with this, get a dedicated 120 volt 14-50 amp service installed and be done with it. I have seen electricians that did not know how to correctly wire a RV service outlet. A 50 amp RV service is two legs 120 volt, a ground and a neutral.
Do not connect it to your dryer plug end of story.
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Show this to your electrician. If he doesn't understand it, then find a different one. You are talking about burning up every thing electrical in your coach (the smoke is horrible) if this isn't wired correctly.
Even after he wires it, before you plug the RV in, connect a pigtail that gets you from 30A to 15-20A, and plug in a lamp. If the bulb explodes, he did it wrong.
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Lee is correct there is a difference between your three prong dryer plug and a 3 prong RV plug to 3 prong dryer plug is a 240-volt circuit whereas the three prong RV plug is a hundred 120 volt circuit .
the two diagonal pins on the three prong RV plug are a black 120 volt wire and a white common wire, which is 0 volt the third pin is actually the ground .
on your dryer plug the three prongs are a red wire which is 120 volts phase 1 and the another is a red wire which is 120 volts phase 2which will give you 240 volts the third prong is again just a ground without the common wire you cannot get 120 volts out of the dryer plug with out cheating and this is where the problem lies as the cheats are not legal and would not be covered by your insurance if something went wrong.
Hope this helps explain
Eric