Portable Generator question

[GerryB]

My customer has a 10k generac portable. He has been backing up his house, large home, 400 amp service, for years with this generator and says he can run everything. He had a setup in his detached garage where he would plug in. He wants me to put the plug outside, so I bought the 50 amp power inlet box, cord, and 50 amp twistlocks for both ends. Turns out the 50 amp outlet on the genny is 3 prong straight blade. I am wondering why that is since there is an LR30 right next to it. I was thinking I could use the straight blade on one end and the twistlock and input box on the other, but what about the ground? I see generac has a tech email line I will try to ask them about it. (I thought maybe someone changed that outlet but HO said no.)

 

[iceworm]

... He has been backing up his house, large home, 400 amp service, for years with this generator and says he can run everything. ... Turns out the 50 amp outlet on the genny is 3 prong straight blade. ..

but what about the ground? ...

Probably the answer is the gen is really old and manufactured when it was okay for the output to combine N and G, three prong. 50A repectacle likely looks like a range receptacle.

Q: Did you check the 3prong 50A and see if it did have a neutral and was not just 1ph 240V with a frame ground and no neutral? Reason I ask, is I had a Lincoln Welder (years back and it was old then - but it had a good 1800rpm Yanmar diesel) that the aux output was a 3 prong, 240V 1ph (no neutral). the third prong was a frame ground. Yep - 240 floated.

The other aux output was two duplex 120v receptacles, each with their own 20A CB - not connected to the 240V winding.

Couldn't beleive it, so I tore the covers off and traced the wiring - figured there had to be a broken connection. Nope 240V winding was not connected wth a neutral or to the 120V output winding. :?:? Never figured out why someone would design like that.

ice

 

[mjf]

I have a genny with a 30 amp 240v straight blade receptacle. I have a friend that has a 50 amp one like you described. the receptacle is not like an old 3 prong range receptacle, the configuration is different.

 

[GerryB]

Probably the answer is the gen is really old and manufactured when it was okay for the output to combine N and G, three prong. 50A repectacle likely looks like a range receptacle.

Q: Did you check the 3prong 50A and see if it did have a neutral and was not just 1ph 240V with a frame ground and no neutral? Reason I ask, is I had a Lincoln Welder (years back and it was old then - but it had a good 1800rpm Yanmar diesel) that the aux output was a 3 prong, 240V 1ph (no neutral). the third prong was a frame ground. Yep - 240 floated.

The other aux output was two duplex 120v receptacles, each with their own 20A CB - not connected to the 240V winding.

Couldn't beleive it, so I tore the covers off and traced the wiring - figured there had to be a broken connection. Nope 240V winding was not connected wth a neutral or to the 120V output winding. :?:? Never figured out why someone would design like that.

ice

I would say it has to be a neutral, there is a ground on the genny but nothing connected to it. (on wheels, moves it around) My plan is to put in the power inlet box and make up the cord with the twistlock on one end and the straight blade on the other. If he gets a new generator the one end can be changed. The inlet box would be grounded, just the cord I guess wouldn't be.

 

[GoldDigger]

Since the connection to the house will be a new installation and the generator will not be grounded, I think that you will have to run an EGC to the generator separate from any neutral.
If that requires hard wiring at the generator end or replacing the socket, I think you have no choice.

 

[GerryB]

Since the connection to the house will be a new installation and the generator will not be grounded, I think that you will have to run an EGC to the generator separate from any neutral.
If that requires hard wiring at the generator end or replacing the socket, I think you have no choice.

I was considering replacing the socket on the generator and will bring one with me when I go back.

 

[kwired]

Is the receptacle in question a 10-50 (3 wire range receptacle with 2 hots and a neutral) or a 6-50 (50 amp 250 volts - no neutral but an equipment grounding conductor. Commonly found on welders.)?

Depending on the age of the unit the 10-50 may have been common a long time ago. For the past 20-25 years or so it likely would utilize a 14-50 receptacle (4 wire range receptacle with separate neutral and equipment ground conductors - and the EGC likely only bonds to the generator frame and is isolated from the neutral) and not the 10-50.

6-50 would have been more for specific purpose and wouldn't be as common as something with a neutral connection, I would think.

Was the original receptacle on this generator possibly replaced with a different type?

 

[GerryB]

Is the receptacle in question a 10-50 (3 wire range receptacle with 2 hots and a neutral) or a 6-50 (50 amp 250 volts - no neutral but an equipment grounding conductor. Commonly found on welders.)?

Depending on the age of the unit the 10-50 may have been common a long time ago. For the past 20-25 years or so it likely would utilize a 14-50 receptacle (4 wire range receptacle with separate neutral and equipment ground conductors - and the EGC likely only bonds to the generator frame and is isolated from the neutral) and not the 10-50.

6-50 would have been more for specific purpose and wouldn't be as common as something with a neutral connection, I would think.

Was the original receptacle on this generator possibly replaced with a different type?

It's the 10-50 (blades on an angle) range and it was never changed according to HO.

 

[kwired]

It's the 10-50 (blades on an angle) range and it was never changed according to HO.

Unit probably has some age to it as well?

 

[iceworm]

I would say it has to be a neutral, there is a ground on the genny but nothing connected to it. ...

Just a suggestion - Might want to check and know for sure.

ice