David C. Roseman
10-01-2013, 10:24 AM
Below is a question I posted a few days ago in a thread on Chinese gensets in an RV forum. So far no replies, so I thought I'd repost it verbatim here in the hopes the bright folks on this board might be able to help. :) Thanks in advance to anyone who takes the time to wade through this!
Hope someone can answer a basic question for me on the attached wiring diagram from a 5 or 6 y/o Nikota 3500/3000w generator. Maybe even Prof. Agee will weigh in, as this relates to one of his earliest posts on this epic 8 y/o thread! http://www.rv.net/SharedContent/cfb/images/smile.gif
I use the genset for light-duty portability. It runs well, producing 240v at the NEMA L14-30 receptacle and 120v at the duplex receptacle. A 4P2T toggle switch selects the voltage between 240 and 120. The wiring to the L14-30 receptacle is straight forward, with the brown feed from the first phase (call it Phase 1) providing 120v on one terminal, and the blue wire from the other phase (Phase 2) feeding 120v to the opposite terminal. Since the feeds are 180 degrees out of phase, 240v is the result across those terminals. A few years ago, I added a neutral where there originally was none so I also have 120v from the L14-30 receptacle when needed, but that's the only mod that's been done.
So far so good. What has puzzled me is the way the 120v circuit is wired. As shown on the attached diagram, when the 4P2T is switched to 120v, the brown feed from Phase 1 connects to the hot side of the duplex receptacle, yet the blue feed from Phase 2 connects to the neutral side, on the opposite side of the receptacle. Surprising to me is that the jumper plates are fully intact on both sides of the receptacle. Question: Why doesn’t this yield 240v across the terminals of the duplex, just as it does with the L14-30 when the selector switch is set to 240v? And, even more basically, why doesn’t a ground fault occur due to the blue feed being connected directly to the neutral side of the duplex receptacle by virtue of the intact jumper plate?
Apologies if this has already be asked and answered somewhere in this thread. I did find a good post by Prof. Agee dated 3-16-05. Here's the link to that forum page.
But the Nikota 3500/3000 wiring diagram in Prof. Agee's post is quite different from mine. It shows the leads from Phase 1 and Phase 2 both connecting to the hot side of the duplex receptacle, and the jumper cut on the hot side to produce two separate receptacles. That seems completely intuitive to me; mine not so much.
Here is a pic of my wiring diagram, if this link works:
http://s279.photobucket.com/user/dcroseman/media/Nikota%20genset/Nikotawiringdiagramresized9-24-13_zps6a8069b6.jpg.html?sort=3&o=0
David
Hope someone can answer a basic question for me on the attached wiring diagram from a 5 or 6 y/o Nikota 3500/3000w generator. Maybe even Prof. Agee will weigh in, as this relates to one of his earliest posts on this epic 8 y/o thread! http://www.rv.net/SharedContent/cfb/images/smile.gif
I use the genset for light-duty portability. It runs well, producing 240v at the NEMA L14-30 receptacle and 120v at the duplex receptacle. A 4P2T toggle switch selects the voltage between 240 and 120. The wiring to the L14-30 receptacle is straight forward, with the brown feed from the first phase (call it Phase 1) providing 120v on one terminal, and the blue wire from the other phase (Phase 2) feeding 120v to the opposite terminal. Since the feeds are 180 degrees out of phase, 240v is the result across those terminals. A few years ago, I added a neutral where there originally was none so I also have 120v from the L14-30 receptacle when needed, but that's the only mod that's been done.
So far so good. What has puzzled me is the way the 120v circuit is wired. As shown on the attached diagram, when the 4P2T is switched to 120v, the brown feed from Phase 1 connects to the hot side of the duplex receptacle, yet the blue feed from Phase 2 connects to the neutral side, on the opposite side of the receptacle. Surprising to me is that the jumper plates are fully intact on both sides of the receptacle. Question: Why doesn’t this yield 240v across the terminals of the duplex, just as it does with the L14-30 when the selector switch is set to 240v? And, even more basically, why doesn’t a ground fault occur due to the blue feed being connected directly to the neutral side of the duplex receptacle by virtue of the intact jumper plate?
Apologies if this has already be asked and answered somewhere in this thread. I did find a good post by Prof. Agee dated 3-16-05. Here's the link to that forum page.
But the Nikota 3500/3000 wiring diagram in Prof. Agee's post is quite different from mine. It shows the leads from Phase 1 and Phase 2 both connecting to the hot side of the duplex receptacle, and the jumper cut on the hot side to produce two separate receptacles. That seems completely intuitive to me; mine not so much.
Here is a pic of my wiring diagram, if this link works:
http://s279.photobucket.com/user/dcroseman/media/Nikota%20genset/Nikotawiringdiagramresized9-24-13_zps6a8069b6.jpg.html?sort=3&o=0
David