M109a3 Shore Power Cord ?

[peashooter]

Ive got an 88 m109a3 and am trying to figure out what I've got here? This is the 4 pin power cord plug/receptacle coming off my box. All the other 109 units I've seen have a 2 pin. Does anyone know why & when they changed over to this 4 pin style? I'll probably be converting it all to lighter gauge rv connections since a 60 amp line is too massive for my needs/storage of the cable, but would like some background on this.

Thanks for any help

 

[SCSG-G4]

I'm using a Marinco 30 amp in mine (see 'a different M108 conversion' for pics). Looks like they wanted three phase power in your box, probably for a motor. Two wire is usually just regular 110v.

 

[wsucougarx]

Interesting! Do you have any added power outlets or power cables in your van box itself?

 

[Floridianson]

Looks like two large and two small. The two small would be ground. My new style has 4 small pins and they are all ground. I don't know much about shocky stuff but looks like they want to make shure that ground can handel and gets back to the Gen. ground rod and not the truck/box.

 

[peashooter]

Thanks guys.
There arent any extra outlets or wires in the box other the standard power strips. Although there are 1 or 2 ground fault outlets that the airforce must have installed, not sure if those are typical with the older m109s or not.
I havent gotten around to opening up any of the electrical enclosures yet (too many other things to address first), but I appreciate the info. My guess was also that the 2 "extra" pins/wires were ground but I've only seen double grounds when a single conductor wouldnt be flexible enough so they go with 2 smaller cables.... but that doesnt seem like it would make sense for this app. Could the extra grounds be required/used for the GFCI's? Guess I'll have to open things up to check it out.
The 2 large pins are white and black wires (hot and neutral I assume), the smaller 2 pins are both smaller black wires..... if they were green it would be a little more obvious as to there use.

 

[cranetruck]

Here is a similar plug on an m43 modified in 1959. Apparently power for air conditioning/heater, lights and a computer system...

 

[Floridianson]

Here is my 100 amp plug with 4 main and 4 grounds.
the outher pics are some cables I have whth 4 main and one ground.

 

[islasaero]

From what I understand

I really need help and would be happy to hear from you. My M109 Has two recepticles. One for the 24v system and another to connect to a 115v generator or something like that? I check the whole wiring and connected the two pin 24v system to the batteries. Once, I found that all the wiring was in good condition, I decided to turn on the truck thinking I would get 115v running thru. But, it just stayed 28v with engine running. So, i figured there is no power inverter. I was hoping it did!! So, My question is, what gets connected to the red 4 pin recepticle? I will have to run 2 power inverters to run a 220v cooktop? Should I replace the electrical panel?

 

[wsucougarx]

I have seen AC units use the lower plug for their power

 

[SCSG-G4]

Floridason,

Your cables with the four mains actually have four each 12 ga wires all bundled together going to the ground pin. I disassembled the end off one of the cables I bought from you so I could hook it into a generator (MEP003A) panel.

 

[peashooter]

I really need help and would be happy to hear from you. My M109 Has two recepticles. One for the 24v system and another to connect to a 115v generator or something like that? I check the whole wiring and connected the two pin 24v system to the batteries. Once, I found that all the wiring was in good condition, I decided to turn on the truck thinking I would get 115v running thru. But, it just stayed 28v with engine running. So, i figured there is no power inverter. I was hoping it did!! So, My question is, what gets connected to the red 4 pin recepticle? I will have to run 2 power inverters to run a 220v cooktop? Should I replace the electrical panel?

I think their is an inverter just for the vent fan so you wouldnt want to run anything else off of it. The inverter is inside the largest box that has all the heater/vent fan switches on it.
The 4 pin connector is for a shore power cable. The cable would connect to a outside power source like a generator or 120 volt outlet. The 4 pins are most likly 120v hot, neutral, and 2 grounds. This is what supplys 120v power to your truck. If you want to run 220v, I suspect you would need to start from scratch on that and either rewire most of it or add a seperate panel/power input just for your stove. I personally would go a different route for the stove, perhaps propane or something. a 220v stove will still require tons of amperage and I cant imagine any inverter being able to handle that.

 

[islandguydon]

Follow the power inlet's to their destination, verify it's AC or Dc. then be sure if it's AC the equipment is not rated for 400MHZ, I think the 4 prong is for a 3ph 400MHZ power supply off a MEP.

Don

 

[islasaero]

I checked all connections

Ok, the 4 prong on my m109 only has 3 wires to it that connect to the cab. My electrical panel is only capable of 250v max, which is all I need. At most RV parks, they have 220V outlets for RVs with a lot of equipment. I will be able to install a 220v cooktop that I got without a problem. I will change the original MEP plug for a brand new Meltric Decontactor plug. I was just wondering on how to wire the neutral wire since I only have 2 hot and 1 ground....Guess I'll check my own panel fo that or ask my friend who's an electrician. I'm hoping to just get an inverter for the interior lights while I drive and my friends/ familly are inside.

 

[peashooter]

Ok, the 4 prong on my m109 only has 3 wires to it that connect to the cab. My electrical panel is only capable of 250v max, which is all I need. At most RV parks, they have 220V outlets for RVs with a lot of equipment. I will be able to install a 220v cooktop that I got without a problem. I will change the original MEP plug for a brand new Meltric Decontactor plug. I was just wondering on how to wire the neutral wire since I only have 2 hot and 1 ground....Guess I'll check my own panel fo that or ask my friend who's an electrician. I'm hoping to just get an inverter for the interior lights while I drive and my friends/ familly are inside.

Doesnt your 109 box have the 2 or 3 24v lights (the ones down the center of the box roof) that run off the batteries? Or were you looking for an inverter to run the other 5 white 120v lights when not connected to shore power?

 

[islasaero]

Sure does, I tested those using a thick wire. My 110v lights work too, but dim cause it's only 24volts.It does have the two pin receptacle. And, yes, I am looking to run the lights while not connected to an rv outlet. I just removed the four pin receptacle to upgrade, plus, I can't find the plug. Too late if anyone has it for sale. The Meltric can disconnect internaly if there happens to be a short. Plus, it's water tight. I got it from ebay for $65. All it needed was the handle and the cord.

 

[SCSG-G4]

If you did find the plug, you would go the way you did in an even bigger hurry. Best price I've seen was $176 and change Plus Shipping! And no wire attached either. I swapped mine out with the Marinco 30 amp and use their big cords (30 A, 50 ft) for shore power hookup. I also have RV converter cables and a PDU that I can use with the generator.

 

[islasaero]

Well, I found out that my Meltric Plug and receptacle has extra slots for more phase pins. So, since I need to have two positives, a ground, and a neutral, I'll buy another Meltric DSR, 50amp plug and recepticle, and take out a phase plug to add to my other combo. I'm only doing that cause the distributor that sells the extra parts was asking for $100. Way too much! So, If anyone wants to upgrade their wiring, and plan on the same plug/recepticle as me (check ebay for Meltric DSR 50amp from a seller for $65 total, seller bybirius from Atlanta, GA) and I can sell u the extra phase pin u need for the RV 220v connection at a low price. So, I have two, will part one and sell the parts to benefit us all. if you need more info about my Meltric plug, check out their site under literature, Decontactor, Nema 3R, water tight plugs.http://www.meltric.com/pdfs/2011-2012-catalog/2011-decontactor.pdf
The images are of my truck. I covered the old holes and drilled and tapped new ones. What a pain! Anyway, Im just waiting on the handle and the to install the extra pin so as to finish the installation.

 

[islasaero]

Just wanted to show the extra Meltric receptacle and plug I got. It dissassembles with ease. So I took out a spring loaded pin and added it to the first recepticle and plug. Now it has 2 positives, negative, and a neutral. I'm planning on isolating the ground cause I've heard of rv horror stories. I also found out (after the sparks)that the 24v lights in the camper are always connected. I thought I had to buy the two pin plugs to connect that, but, I'm glad I dont have to.