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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => AC Power and Grounding => Topic started by: Larry Sheehan on April 17, 2015, 11:04:09 AM
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I just got a Peavey distro, and have been reading up on adapters to allow it's use with different capacity supplies.
It comes with Nema 14-50 Male. There are Camco adapters (dogbones) to allow it to be connected to Nema 14-30 consisting of NEMA 14-50 Female to NEMA 14-30 Male. I am wondering whether the loss of a pin is safe? I think that internally it must be wired to that the safety ground and neutral are consistent, and the Hot is connected from the hot of the 14-30 to both hot of the 14-50. This would provide a single phase 30 amp.
Is this correct? And more to the point, it appears that if this is how it works internally that it SHOULD be safe.
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I just got a Peavey distro, and have been reading up on adapters to allow it's use with different capacity supplies.
It comes with Nema 14-50 Male. There are Camco adapters (dogbones) to allow it to be connected to Nema 14-30 consisting of NEMA 14-50 Female to NEMA 14-30 Male. I am wondering whether the loss of a pin is safe? I think that internally it must be wired to that the safety ground and neutral are consistent, and the Hot is connected from the hot of the 14-30 to both hot of the 14-50. This would provide a single phase 30 amp.
Is this correct? And more to the point, it appears that if this is how it works internally that it SHOULD be safe.
Take a look at an article I wrote: http://tjcornish.com/articles/power-distribution-part-3--.html
Almost half of it deals with adapting distros to other plugs - what's ok/not ok, and some theory.
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I just got a Peavey distro, and have been reading up on adapters to allow it's use with different capacity supplies.
It comes with Nema 14-50 Male. There are Camco adapters (dogbones) to allow it to be connected to Nema 14-30 consisting of NEMA 14-50 Female to NEMA 14-30 Male. I am wondering whether the loss of a pin is safe? I think that internally it must be wired to that the safety ground and neutral are consistent, and the Hot is connected from the hot of the 14-30 to both hot of the 14-50. This would provide a single phase 30 amp.
Is this correct? And more to the point, it appears that if this is how it works internally that it SHOULD be safe.
BTW, there is no loss of a pin going from a 14-50 to a 14-30. They are both 4-wire devices in the same series - HHNG. The only difference is the current capacity.
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BTW, there is no loss of a pin going from a 14-50 to a 14-30. They are both 4-wire devices in the same series - HHNG. The only difference is the current capacity.
Thanks, Tom. Great paper.
Got 14-30 confused with 10-30 which is where I thought I'd lost a pin.
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My only concern about adapting to a 30A circuit is now you have 6 circuits, each with 20A breakers, and you're splitting that amongst 60A instead of 100A. That drops your average of 16.334A down to 10A per circuit available. If you use all six circuits and are hitting it hard, you could pop the L14-30 breaker before any of the 20A breakers on the distro trip-- and that breaker might be inconveniently located for during-show resets.
I almost feel like I'd want to set things up where one breaker has a couple of things on it that most of the time, you'd be fine under 20A, but if you push it hard, that breaker would trip, and being a local breaker, it's easier to find and reset in a hurry. Put stage power on its own breaker, and FOh on another one. This way, even if you lose part of the PA, everything else is still chumming along fine. You lose the main upstream breaker, that's show over until it's reset, and is immediately noticeable to everyone. (If you just lost miss for a bit, or highs, people won't notice *as fast* as they would the whole kit being out.)
-Ray "raging paranoia about power loss" Aberle
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My only concern about adapting to a 30A circuit is now you have 6 circuits, each with 20A breakers, and you're splitting that amongst 60A instead of 100A. That drops your average of 16.334A down to 10A per circuit available. If you use all six circuits and are hitting it hard, you could pop the L14-30 breaker before any of the 20A breakers on the distro trip-- and that breaker might be inconveniently located for during-show resets.
I almost feel like I'd want to set things up where one breaker has a couple of things on it that most of the time, you'd be fine under 20A, but if you push it hard, that breaker would trip, and being a local breaker, it's easier to find and reset in a hurry. Put stage power on its own breaker, and FOh on another one. This way, even if you lose part of the PA, everything else is still chumming along fine. You lose the main upstream breaker, that's show over until it's reset, and is immediately noticeable to everyone. (If you just lost miss for a bit, or highs, people won't notice *as fast* as they would the whole kit being out.)
-Ray "raging paranoia about power loss" Aberle
Good point, Ray, thanks. I think this "derating" would be the exception, rather than the rule, but I'll skull it over with this info in mind.