30 Amp to 50 Amp Connection for Generator

adam

Well-known member
Good Afternoon,


I have a new Key Largo, it is equipped with a transfer switch and simple surge protector. The unit is also equipped with factory generator prep.

I will be using a Yamaha 3000 iseb generator for boondocking and I would like to hardwire a 30 Amp (3 wire) generator extension cord to the generator prep box which currently has a 50 Amp (4 wire) installation. I have 2 questions I need help with;

Where should I bond the single line feed from the generator to the 2 hot legs feeding the RV? Should that be done in the generator prep box or the transfer switch?
Will I still require a Neutral to Ground bond? (because my Yamaha is a floating neutral type generator)

Pics show;
the generator prep box
the transfer switch (generator feed at top and shore feed at bottom)
generator side tied to output side of transfer switch



Thanks
Adam Hunter
 

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adam

Well-known member
Thanks Bob,

The 50 amp power cord will still need a extension cord to reach the generator in the truck. We were also hoping to have a 2nd 30 amp cord in the front for those odd ball sites like our provincial parks where the power pedestal is not always in a common place. Finally I would prefer to just pull a few feet of cord out of the battery compartment to reach the generator in the pick-up bed instead of long cable lengths when we are doing road trips and need some quick power while travelling.

But I do appreciate the simplicity of what you are suggesting.


Adam
 

adam

Well-known member
Thanks Jim,

Your quotation contained 3 lines that I did not type, please see my original post. I'm not sure where that info came from?

With respect to your comments I fully understand that RV's do not use floating neutral. I indicated that my Yamaha inverter gernerator was however floating. The second part of my question was to see how other members where dealing with floating neutral generators and the transfer switch in late model production units.


Thanks Adam.
 

Jim.Allison

Well-known member
I deleted it and re-posted. Sorry:cool:

Thanks Jim,

Your quotation contained 3 lines that I did not type, please see my original post. I'm not sure where that info came from?

With respect to your comments I fully understand that RV's do not use floating neutral. I indicated that my Yamaha inverter gernerator was however floating. The second part of my question was to see how other members where dealing with floating neutral generators and the transfer switch in late model production units.


Thanks Adam.
 

brianharrison

Well-known member
Hi Adam,

I ganged together the 2 hots in the generator box with the single hot coming from a new 30A connection in the front of my trailer.

I am suspecting the OEM onboard surge/EMS is upstream of the transfer switch. I suspect an OEM onboard ONAN would have the same floating neutral? Others with a factory surge/EMS and gen prep or gen should be able to chime in and confirm.

Take care,
Brian
 

Jim.Allison

Well-known member
I don't think Gen Prep includes EMS. But use caution whatever you do. The transfer switch has a lockout on it and will burn up when you start the generator. I know from experience.

Im confused by your terminology. So I deleted my original comments. It suffices to say that neutrals and grounds are never bonded except at the source of the electricity.
 

porthole

Retired
Will I still require a Neutral to Ground bond? (because my Yamaha is a floating neutral type generator)


You don't have to do anything with the generator. But, if you have something like a progressive EMS it will not pass power because of the float. And some electrical equipment will not work without that bond. For example, my HE water heater in the house will not operate with the un bonded neutral ground.


A common way to correct this without dissembling the generator is to take a standard 15 amp replacement plug and jump the neutral and ground in the plug. Then plug this into one of the open 15 amp circuits on the generator. That's a trick that came from the Honda people years ago.
 

adam

Well-known member
thanks Duane,

So I am assuming that you use a external genertor with your 3010. How do you have your gnerator wired?


Adam
 

porthole

Retired
Our trailer has a genny. Most of the time I will use that, as it is already there.
But, when we boon dock for an extended time, mostly the Dover NASCAR races, I will also bring the Honda 3000 with us.

I will use the trailer's genny for when we need the extra power, like during the day and 2 AC's.
At night or when we really don't need 5500 watts I'll switch to the Honda and run it in economy mode.
I lock the Honda to the rear of the trailer and just use my 50 amp cord with a "generator" adapter and dog bone.

The generator adapter is a 30 amp 3 prong to 30 amp twistlock adapter.
The dog bone is a 50 --> 30 amp adapter.

My trailer has the 50 amp power cord on an electric reel, so that makes it a bit easier to deal with.
 

Gaffer

Well-known member
Put a 50 amp receptacle on the pigtail. Plug a Progressive EMS into the receptacle and a dogbone onto the EMS. Then all you need is a 30 amp extension cord. This should be no different than running from the generator through a dogbone and EMS to the shore power cord which works just fine with my parallel Hondas and Progressive EMS.
 

adam

Well-known member
Thanks everyone for all of your kind input. I now have enough information to set the generator system up so it works safely.


Much thanks

Adam Hunter
 

porthole

Retired
Adam, it looks like you are looking for some versatility.

"IF" it was my trailer and trying to accomplish what I think you are trying to do, I would:

Add a 50 amp receptacle at the front of the trailer where it works best for you. This would have to be wired into your transfer switch.

Marine grade Marinco brand would be my first, but pricey choice. This connector would allow a gasketed, twist on cap.

Marinco 6373EL Marine 4-Wire Stainless Steel Locking Power Inlet (50-Amp, 125/250-Volt, Male)
http://www.amazon.com/Marinco-6373E...07988&sr=8-7&keywords=marinco+50+amp+inlet+50

Next I would make up an extension cord. You "might" find what you already need, but it is unlikely
My choices here would be to get a Marinco brand part again.

Marinco 6364CRN Marine 3-Pole 4-Wire Electrical Connector (50-Amp, 125/250-Volt, Female)
http://www.amazon.com/Marinco-6364C...08185&sr=8-8&keywords=marinco+50+amp+inlet+50

This cover for the above plug

Marinco 7715CRN Weatherproof Cover with Threaded Ring for Marinco Marine Electrical 50-Amp Connectors (6360CRN and 6364CRN, Female Conncectors)
http://www.amazon.com/Marinco-7715C..._sim_sg_1?ie=UTF8&refRID=0109M5K5T5VW9NKEXBYS

Next would be to either find a 30 amp twist lock male plug and some 10 gauge wire (length that you need, "SO" wire from home depot - lowes etc). Or, just buy an extension cord and replace the the female end with the above 50 amp plug.

Marinco EEL 30-Amp 125-Volt Cord Set, Yellow, 12-Feet
http://www.amazon.com/Marinco-30-Am...e=UTF8&qid=1406809057&sr=1-5&keywords=CS30-12

A longer cord, 25' maybe if you will be planning to use the front inlet at those "special" parks.

And lastly, I would get the hardwired version of the Progressive EMS. Wire it in after your transfer switch, that way you have the EMS protection from either inlet.
The Progressive EMS is more then just a surge guard and is superior to what you have from the factory.

If you go into your transfer switch for any additions, it would also be a good time to make sure all the connections are tight.

So I just spent under $500 of your hard earned $$$, but it gives you some flexibility.

If you live near a Marina that is a good place to check for shore power cords. Boaters are always overloading the cord sets and burning out the plugs then throwing them away. Replace the ends and you have new extension cords.

I wouldn't use repaired shore power cords at a dock, but for around home and RV'ing there is nothing wrong with them.


******************************* addition *************************

To use the same "front" extension cord for either RV to park pedestal or to the genset, use a 30 amp RV cord, the 50 amp replacement connector listed above and get the RV to genset adapter.

30 amp adapter
http://www.campingworld.com/shoppin...0-amp-twist-lock-male-generator-adapter/69591
 

wdk450

Well-known member
Its kind of funny that bonding the neutral to ground on RV generators is "for safety" and NOT bonding the neutral to ground in portable generators is also "for safety".

Agreed that the EMS doesn't like ungrounded neutrals and would have to be bypassed with the bypass switch.

30 amp RV extension cords are available at Walmart for about $50.

I built a corded 30 amp RV GFI box to go inline from my generator if I ever use it again. I guess I should have used it a few weeks ago when I got shocked from a 30 amp RV park connection with a poor ground. Woodhead lists the 30 amp inline GFI, but it is pricey. Now I just try to make sure I test the park's outlet with a non-contact voltage tester before ever connecting to it.
 

Jim.Allison

Well-known member
Ditto, run your generator through the transfer switch, It will provide the neutral bond appropriately. If you have an EMS, it should only check pedestal power not your gen power so put it on the shore power line. No need to involve it in checking electricity that you know is good. A transfer switch will transfer to the generator if it is running even if hooked to shore power.

http://www.noshockzone.org/generator-ground-neutral-bonding/
 

Jim.Allison

Well-known member
Gotta get one of these. $15 bucks at lowes.

Its kind of funny that bonding the neutral to ground on RV generators is "for safety" and NOT bonding the neutral to ground in portable generators is also "for safety".

Agreed that the EMS doesn't like ungrounded neutrals and would have to be bypassed with the bypass switch.

30 amp RV extension cords are available at Walmart for about $50.

I built a corded 30 amp RV GFI box to go inline from my generator if I ever use it again. I guess I should have used it a few weeks ago when I got shocked from a 30 amp RV park connection with a poor ground. Woodhead lists the 30 amp inline GFI, but it is pricey. Now I just try to make sure I test the park's outlet with a non-contact voltage tester before ever connecting to it.
 

porthole

Retired
Jim - the OSHA comment was in reference to Bill bringing up portables in general. Although I probably added to the confusion the real confusion is the different requirements for the work place and requirements for recreation.
https://www.osha.gov/OshDoc/data_Hurricane_Facts/grounding_port_generator.pdf

So your Big Country may be just fine out in the boondocks on a portable genny, but as soon as you make it a commercial workplace, you have OSHA to deal with, and the generator has to be bonded and grounded.
It is a fine line to determine on the workplace if your trailer is just plugged into a genny and is not required to be bonded and grounded or you are running through a transfer switch.

The OP is looking to have flexibility, so the EMS needs to be after the transfer switch since he desires to use the front port for park power as well.
Besides, there is no guarantee any portable generator will work 100% correctly, 100% of the time, so no harm in having the EMS cover it all.

We were also hoping to have a 2nd 30 amp cord in the front for those odd ball sites like our provincial parks where the power pedestal is not always in a common place.


The portable generator, at least used through the regular RV port, will not pass through a Progressive EMS with the open ground. The genny needs to be "fooled" with the "bonding plug" As I suggested prior and you verified with Mike Sokol's article.
 

danemayer

Well-known member
If you have an EMS, it should only check pedestal power not your gen power so put it on the shore power line. No need to involve it in checking electricity that you know is good. A transfer switch will transfer to the generator if it is running even if hooked to shore power.
My recent experience with faulty transfer switches argues that a built-in EMS should be after the transfer switch so that it can protect you against transfer switch failures.
 

NWILSON

Kentucky Chapter Leaders - retired
My recent experience with faulty transfer switches argues that a built-in EMS should be after the transfer switch so that it can protect you against transfer switch failures.
I agree! Only seems right that the rig should be protected from a fault on the generator as well.
 
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