Mep-003

[Donaldjerome]

I just bought an mep-003 gen. I am going to use this for back up at my house. I wanted some opinions on hook up. I'm thinking of using a 200amp transfer switch (manual) . I'd like to have a 75 ft (max) cord to get gen away from house. Is #8 copper sufficient? If I can use a smaller transfer switch or wire let me know. I don't like to chince, but stuff is so expensive. I have been reading all the gen. posts on here and the info is great. Thanks all.

 

[LuckyDog]

Check out the WIKI for the MEP 002A and 003A. It is a great place to start.
In the FAQ section, there is link to how to ground the unit correctly. ( I haven't gotten to adding more house connection links yet) Use the search and you will find some threads discussing hooking it up to the house.

 

[LuckyDog]

Ok, did a quick search for you. (I hate when I am told to search, but couldn't resist )

http://www.steelsoldiers.com/auxillary-equipment/40290-mep-003a-hook-up-question.html

I search the forum using: House connecting

House wiring also brought up a bunch more hits.

Happy Reading.

 

[Bill W]

I use 100' 6/4soow cord to run my 003A, got it off e-pay for around $285 delivered

 

[Donaldjerome]

mep-003

Thanks for the info guys. Yes there are some good deals on Fee-bay. Thanks

 

[baxter]

I have been hooking up these gens for friends and on the mep 003 i use the 6-4 so. I also use leviton 4 wire 50amp pin and sleeve cord end and receptiicle in the transfer switch so its easily connected and disconnected.

Vaughn

 

[Isaac-1]

#8 is going to be marginal, as to the 200 amp transfer do you have a 200 amp service to the house and plan to transfer the whole load then manually manage what you have turned on? If so you may want to check out Harbor Freight they often have a very good price (depending on sales) for a 200 amp Cutler Hammer manual transfer switch. Ike

 

[PeterD]

IMHO, (such as it is) you'd probably be OK with 8 AWG for 75 ft. One thing to check is the temperature rating of the wire, if 90c or below, the size is very close to the maximum. If over 90c, then you are in better shape. Of course, for initial runs, carefully monitor the wire's temperature (it will probably get warm at full rated power.)

With my MEP-004, running three phase, I use 10 AWG (three phases, one neutral, one ground), with two 15 amp breakers for each phase (two backup 120 volt circuits per phase). That limits my current to 30 amps. I'd simply size a breaker to match your wire as a safety factor.

 

[Speddmon]

I ran into this situation a little while ago at work about the amperage ratings of type SO power cord. You might be surprised to learn that to be up to snuff by the code amperage ratings of type SO cord you need to use a #4/4 cord for the full power rating of the MEP-003a.

Before everybody get's all up in arms about it...can you get by with #6, YES.

But to be up to code as I mentioned you need to refer to table 400-5(A) of the NEC. That table states that for portable power cables rated at 90 degree C the full load ampacity of a #6 cable with 3 current carrying conductors is only 45 amps. You need to use 3 conductors in your calculations because of the neutral on a 240 volt system. Even though it is the neutral, it still carries current (AC means alternating current so it doesn't just travel over the hot wires). You would need to step up to a #4 awg 4 conductor cable to be rated at 60 amps which will put you over the max 52 amp output of the generator.

Also, so everybody knows, I use #6/4 for my generator hook-up.

 

[runk]

I've been looking at this as well, and have some related questions.

Any reason for the pin/sleeve over the NEMA blade type ? The sources I've found for the pin/sleeve connectors are expensive !

Theoretically (I realize it wouldn't meet code), could a pair of slave cables be used ? The wire would be more then sufficient, but the connectors don't seem to have any sort of AC rating. Although, I always think of DC as the more severe requirement for amperage ratings.

 

[rosco]

GenTran makes a 50 amp power cord with a pin/sleeve plug & recepticle (by 50 feet long). It seems they rate it slightly over the 50 amp rating. I have it hooked into a 200 amp rated transfer switch. I used #4/4 from the outside recepticle into the transfer switch. I always thought that to be safe in an emergency situation, that one should be selective in the total load that one is pulling on the GenSet. In other words, don't be trying to pull 100% and risk a melt down at -50 F. I'd rather do without a few accessories, but keep the lights and furnace on.

 

[steelandcanvas]

Any reason for the pin/sleeve over the NEMA blade type ? The sources I've found for the pin/sleeve connectors are expensive!

Pin and sleeves are extremely expensive! I used a twist-lock with a 4 wire, 250/125 Volt, 50 Amp rating. These plugs/receptacles/cord caps are found on temporary power systems on construction sites. You can get weather seals to cover the cord cap and plug, makes for a real nice set-up. Don't have the number of the units now. I'll post them later if anyone is interested.

 

[pistonium]

For what it may be worth, Square D makes a very inexpensive switch for their service panels that mounts in the upper breaker location of the panel and has a bracket the slides up into the location of the main breaker switch handle. This provides a code approved transfer switch right in your normal panel serving the normal breakers going to the house.

The way it works is this - you wire your genny into the 2 pole breaker in the upper right slot, and it stays disconnected from the busway in the panel unless you move the bracket which forces you to open the main breaker - then you can close the breaker to the genny. This makes connection of the genny to the grid impossible.

The great thing about this is you can select any of your normal loads to run on the genny! AND ITS CHEAP, SAFE and CODE LEGAL.

 

[PeterD]

I ran into this situation a little while ago at work about the amperage ratings of type SO power cord. You might be surprised to learn that to be up to snuff by the code amperage ratings of type SO cord you need to use a #4/4 cord for the full power rating of the MEP-003a.

Before everybody get's all up in arms about it...can you get by with #6, YES.

...

All very good points... An easily accessible site for some wire info is American wire gauge - Wikipedia, the free encyclopedia though those number must be de-rated as the conductors are not single but multiple. One should consider just how much current they are drawing (or want to draw) and just use a circuit breaker sized to protect the wire, rather than trying the size the wire for the generator's maximum output. Anything requiring moving or arranging wire in the winter is a PITA, the stuff gets stiff (even if good rubber cable) and hard to work with...

 

[Donaldjerome]

mep-003

I have a 200 amo service at my house, I probobly will use a 200 amp transfer switch. It would be nice if I could go with a 100 amp switch because the is a huge difference in price! I'll use a 6/4 cord from gen to outdoor receptacle. The sleeve and pin connectors look slick but man they are expensive. Maybe get the wife to go halfsies

 

[Speddmon]

One should consider just how much current they are drawing (or want to draw) and just use a circuit breaker sized to protect the wire, rather than trying the size the wire for the generator's maximum output.

And therein lies the problem...The breakers are designed to protect everything downstream of itself. That's why if you put a sub-panel in your house, but only have 1 20 amp breaker in that box, you still need to feed the sub with wire rated for 60 amps. Because that's the size of the breaker feeding that panel. If you feed it with a 30 amp breaker, then you can get by with only having wire rated at 30 amps.. The generator is capable of putting out 52 amps, and main breaker isn't going to trip until roughly 60 amps or so, if the adjustments are properly set in your machine. You need to size the wire according to what the overload protection is before it, not after. The generator can supply 52 amps, the cable needs to be able to handle 52 amps (to be up to code).

Something has to protect the cable between the generator and the house where the smaller breakers are at. If you had a high resistance ground in that feed cable and it's running through the walls of your garage to get to your transfer panel where the smaller breakers are at. Those smaller breakers are never going to see the large amount of current being drawn by the high resistance ground, only the generator main breaker is...that's why the wire/cable needs to be sized to the full output rating, otherwise, when that wire catches on fire you have no more garage or house.

 

[baxter]

Just to let you know that if you have a 200 amp service you need to use a 200a transfer switch because when you are not running on the gen your transfer switch will be taking the full load of the main service through it. I chose to use the pin and sleeve because it is supported by the housing of the plug instead of the blades carying the current either way is good it was just my choice.
Vaughn

 

[Speddmon]

Vaughn, that is only true for Automatic transfers. When you are using a manual transfer method, it is assumed you are going to be practicing some kind of load management. If you have an automatic transfer and automatic starting generator, then absolutely, YES you must use a 200 amp transfer. A member in FL already went through this just a few months ago and got hammered on his inspection because of the automatic transfer.

 

[baxter]

Speddmon I see where you are coming from, I run the main service through the switch and then I manage the load by what is turned on in the house or shop.

Vaughn

 

[Donaldjerome]

Speddmon:

Assuming I go with a 200 amp transfer switch what size breaker in the main panel where transfer switch is hooked into. I will have to jockey some circuits into my subpanel to make room as the main panel is full. What size wire from breaker to transfer switch #4 (will be short distance 2-3")