Generator question

[dodge man]

I recently bought a generator. Its a 6500 watt Powermate. It has 4 regular 120 volt outlets (20amp), one 30 amp 120 volt outlet which looks like a 3 prong twist lock, and a 30 amp 120/240 volt 4 prong twist lock.

My question is the 4 prong 120/240 outlet. I bought a 120 volt twist lock extension cord that is 25 feet long and splits into 3 120 volt 3 prong outlets. This seems to work just fine, but how do you know if its running 120 or 240 volts? I guess what I'm asking is how does the generator know whats plugged into this outlet 120 or 240? Is it all controlled by how the extension cord is setup and wired?

 

[schmism]

My question is the 4 prong 120/240 outlet. I bought a 120 volt twist lock extension cord that is 25 feet long and splits into 3 120 volt 3 prong outlets. This seems to work just fine, but how do you know if its running 120 or 240 volts? I guess what I'm asking is how does the generator know whats plugged into this outlet 120 or 240? Is it all controlled by how the extension cord is setup and wired?

Its my understanding it works like this.

4 prong is 120v - 120v - com - ground

if wired for 240v the cord uses the 2 "hot" 120v feeds plus perhaps a ground.

if you have an extension cord like you have, they spilt each side of the hot into its own 120v side.

so in short ya it depends on how the cord is wired

 

[dodge man]

Thats what I thought makes sense to me. I was just going to plug in a light bulb to make sure, but now that I think about it, I have a volt meter that I can use to check it.

 

[hr3]

I bought a 120 volt twist lock extension cord that is 25 feet long and splits into 3 120 volt 3 prong outlets.

If this cord is being plugged into the "120v-30amp." outlet then you only have 120 volt anywhere on the cord,, The reason for this outlet is for supplying power to RV's.. Your better off running 2 cords at 20amps each than trying to load up one side of the generator.. Besides you have 30amp breaker protection ,,, what would you plug in to a 30amp circuit at 120volts ???

 

[Transit]

No, the generator supplies all the voltages to its outlets at the same time. What you connect to that outlet is what you get. The 120/240 outlet is just like your home 120/240 power. Hot to hot = 240 volts, hot to neutral = one leg of the 240 circuit [120v] phase A,
The other hot to neutral is the second 120 v, phase B circuit.
Which voltages are on what pin, get a inexpensive volt meter.

You may also look at any number of NEMA sites, match the plug number and see what is on what pin.

 

[grsthegreat]

the 30 qmp 120 volt outlet should have only 3 wires ( hot, neutral and ground)while the 240 volt reeceptacle has 4 wires (hot - hot - neutral -ground). The cord ends will state either 120 volt OR 240 volt. You DO NOT want to wire an extension cord with the wrong ends and accidentally plug a 120 corded item into the 240 volt receptacle.

 

[JB4310]

I recently bought a generator. Its a 6500 watt Powermate. It has 4 regular 120 volt outlets (20amp), one 30 amp 120 volt outlet which looks like a 3 prong twist lock, and a 30 amp 120/240 volt 4 prong twist lock.

My question is the 4 prong 120/240 outlet. I bought a 120 volt twist lock extension cord that is 25 feet long and splits into 3 120 volt 3 prong outlets. This seems to work just fine, but how do you know if its running 120 or 240 volts? I guess what I'm asking is how does the generator know whats plugged into this outlet 120 or 240? Is it all controlled by how the extension cord is setup and wired?

Sounds to me like that 4 prong outlet is for feeding a transfer switch. A and B hot legs, a neutral and a ground between the equipment.

That cord sounds odd, I guess it could be done but have never seen it. if they used both hot legs and shared the neutral to get 2 110 circuits why 3 outlets? why not 2 or 4 to balance the load?

If they just use 1 hot for 1 circuit, why not just use the 3 prong 30 amp outlet instead of the 4 prong.

JB

 

[dodge man]

I bought that cord because it was the only one I could find. It is a four prong, that much I'm sure of. The idea behind this kind of cord, from what I've read, is its heavier duty, so you run this cord in the house, and then plug shorter cords into the main cord.

 

[the fat kid]

I've used that same "4 prong" 240v cord for 5 years in my house. We cut the female end off and hard wired it in my garage panel. When we lose power I kill the main ( at my trim meter) and plug the male end of that hard wired cord into the 240v 4 prong 30amp twistlock spot on generator which then backfeeds my entire house. It's worked well for me for years and we loose power ALOT!!

 

[schmism]

which then backfeeds my entire house. It's worked well for me for years and we loose power ALOT!!

Just make shure you have included the proper main breaker lockout.

as to what i would plug into a single 30 amp 120v circuit?

a single 30 amp extension cord runs into the house were it splits into 2 or 3 cords to power say.... a window AC unit, the refrigerator and toaster oven... or in the winter 2 1800w space heaters.....

 

[JB4310]

I bought that cord because it was the only one I could find. It is a four prong, that much I'm sure of. The idea behind this kind of cord, from what I've read, is its heavier duty, so you run this cord in the house, and then plug shorter cords into the main cord.

Yeah that's pretty much what the 30 amp outlet is for as well.

Does the cord have any tags on it like how many amps it's good for or if it carries more than one circuit?

JB

 

[dodge man]

I'll have to look at the cord tonight. I've been meaning to hook it up and try it out and test it with a volt meter to make sure what volts its putting out, but its been so hot out, I haven't felt like messing with it.

 

[jonyyuma]

I'll have to look at the cord tonight. I've been meaning to hook it up and try it out and test it with a volt meter to make sure what volts its putting out, but its been so hot out, I haven't felt like messing with it.

More than likely, you will find the wire guage imprinted into the side of the cord. 4 wire plug is simply for two hot legs , a neutral and a ground. It will be white for neutral and then green, maybe with yellow stripe for ground. If you are not positive about the hot legs, get help. You don't want to short out the 110 volt stuff in the house??

 

[JB4310]

More than likely, you will find the wire guage imprinted into the side of the cord. 4 wire plug is simply for two hot legs , a neutral and a ground. It will be white for neutral and then green, maybe with yellow stripe for ground. If you are not positive about the hot legs, get help. You don't want to short out the 110 volt stuff in the house??

I'm pretty sure he said it has three 110 volt outlets on it, that's the odd thing.

I must just be for situations where only the 4 prong outlet is available, and is just using one hot leg. On a smaller generator I doubt it would be putting out anymore than the 30 amp 3 prong.

JB

 

[jonyyuma]

I seriously doubt that a gen set that small has 3 hot legs, or three phase output it would be obvious on the internal breaker>>>.......If it has 3 recepticles????

 

[jonyyuma]

Okay, went back to OP#1...cord set up..

 

[Transit]

I seriously doubt that a gen set that small has 3 hot legs, or three phase output it would be obvious on the internal breaker>>>.......If it has 3 recepticles????

A generator that size most likely is not 3 phase.
Two phase like in your home, Hot A, Neutral, Hot B and ground.

 

[techman]

Actually most homes have only single phase. So referring to two phases is incorrect. The dual voltage single phase is referred to as split phase.

The plug on the generator is likely a NEMA L14-30, which is a 3 pole, 4 wire grounding twist lock plug. The two hot legs are the two opposing from the keyed prong. The keyed prong is ground and the blade opposite ground is neutral. You should be able to use an ohmeter to confirm it.

At max load the genset will deliver 27 amps per leg.

As far as tying it into the panel, BE CAREFUL. You should have an interlock to meet code. the cheapest solution is something like: Generator InterLock Kit Turning off the main is nice, but forget once and you could fry a lineman.

Paul

 

[the fat kid]

Yes I do have a shutoff. Very true I would never ever want to hurt a lineman when power kicks back on. I shut off the main at the trim as a secondary precaution. ( mostly cuz I never trust something without a backup). My master electrician friend wired it for me

 

[JB4310]

I saw this cord at Lowe's today, using the 4 prong 120/240 outlet.

This one has four 120 volt, 20amp receptacles. 2 have a blue marker and two are marked red.

Though it doesn't say it, I'm assuming it is 2 circuits carried by this cord.
An alternative to a transfer switch, where you could have a balanced draw on a single cord coming in the house.

I noticed none of the gennys had the 30 amp 120 outlet, just that 120/240.

JB