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Author Topic: Female nema receptacles powered boxes.  (Read 8124 times)

paul bell

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Re: Female nema receptacles powered boxes.
« Reply #30 on: October 19, 2014, 08:11:50 am »

While it's against the electrical code to "loop through" things like installed lighting fixtures (conduit feeds a fixture, conduit comes out and feeds another fixture), I don't see how it violates any code to have power in & out connectors on a professional speaker or lighting fixture that's UL listed and used with removable connectors that deem it "temporary".

If you run into a difficult electrical or fire inspector, point out the UL approval and the fact that it's being used temporarily.

And ground loops? So long as every connected device is grounded you'll be fine.
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paul bell

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Re: Female nema receptacles powered boxes.
« Reply #31 on: October 19, 2014, 08:26:46 am »

Installed lighting fixture looping:

« Last Edit: October 19, 2014, 11:22:53 am by paul bell »
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Craig Hauber

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Re: Female nema receptacles powered boxes.
« Reply #32 on: October 19, 2014, 03:39:46 pm »

Not sure if this has been discussed before but I think it would be a good idea if manufacturers installed a Nema female receptacle in the back of powered boxes.
It would just make it easier to connect a second box - like a mid from a sub. Less outlets to find and keeps things neat.

I never split the two cabs between different circuits-just the 2 sides if available.
I am surprised this hasn't been done. Or maybe it has and I haven't come across any cabs yet that offer this.

Not sure what you mean by "nema" connectors (-isn't everything approved in the US technically a "nema" connector?)
example: http://www.uniteduniversal.com/nema.html

For IEC connectorized stuff I've always used cords like this from the "dark side" (the computer industry)
http://www.cyberguys.com/product-details/?productid=47179
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Craig Hauber
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Rob Spence

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Re: Female nema receptacles powered boxes.
« Reply #33 on: October 19, 2014, 05:36:26 pm »

Not sure what you mean by "nema" connectors (-isn't everything approved in the US technically a "nema" connector?)
example: http://www.uniteduniversal.com/nema.html

Nope.

Most common ones are. CS connectors (50a, 120/240v turn lock) are not.

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rob at lynxaudioservices dot com

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paul bell

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Re: Female nema receptacles powered boxes.
« Reply #34 on: October 20, 2014, 02:27:33 am »

Hey Rob!

I realize this is far off the original topic but it should be stated that the 50 amp Hubble "California" plugs, while not NEMA listed (National Electrical Manufacturers Association-not a approval agency) they are UL approved and should be allowed in use. Many generators have them installed on their panels.

Note that they top out at three pole, four wire so they can't be used for three hots, neutral & ground.

http://www.lockingpowercords.com/Category/31-50a-plugs-and-connectors.aspx
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Phillip McVea

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Re: Female nema receptacles powered boxes.
« Reply #35 on: October 23, 2014, 12:05:14 am »

Not sure if this has been discussed before but I think it would be a good idea if manufacturers installed a Nema female receptacle in the back of powered boxes.
It would just make it easier to connect a second box - like a mid from a sub. Less outlets to find and keeps things neat.

I never split the two cabs between different circuits-just the 2 sides if available.
I am surprised this hasn't been done. Or maybe it has and I haven't come across any cabs yet that offer this.

The reason you see "daisy-chain" power connections on lighting fixtures, computing equipment, etc. and not loudspeakers is because it's simply too difficult to predict the total power draw of one audio amplifier, none the less multiple units of them connected together.

Obviously, you can only draw so much electricity though a single power cord. The variation in power draw that audio signal amplifiers create is too volatile and expansive to connect multiple units together and be sure you'll still be at a safe/reasonable power draw limit.

It's not that it's impossible, unfeasible, useless, etc. It's just that it's a hard thing to do safely.
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Scott Holtzman

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Re: Female nema receptacles powered boxes.
« Reply #36 on: October 23, 2014, 12:11:40 am »

The reason you see "daisy-chain" power connections on lighting fixtures, computing equipment, etc. and not loudspeakers is because it's simply too difficult to predict the total power draw of one audio amplifier, none the less multiple units of them connected together.

Obviously, you can only draw so much electricity though a single power cord. The variation in power draw that audio signal amplifiers create is too volatile and expansive to connect multiple units together and be sure you'll still be at a safe/reasonable power draw limit.

It's not that it's impossible, unfeasible, useless, etc. It's just that it's a hard thing to do safely.

JBL VRX932, RCF HDL20 I am sure many do.  Computer power supplies use to have a NEMA outlet for the monitor.  So if a consumer can calculate total power draw one would think an engineer operating tens of thousands of dollars of hardware could.  That's also why God invented over current protection, the power outlet and the twofer.
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Scott AKA "Skyking" Holtzman

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Jonathan Johnson

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Re: Female nema receptacles powered boxes.
« Reply #37 on: October 23, 2014, 01:45:30 am »

Computer power supplies use to have a NEMA outlet for the monitor.

BZZZT, wrong answer. To pick a nit, those were IEC receptacles, not NEMA, used in AT power supplies. (Well, maybe some very early ones had NEMA 5-15R, but all the ones I ever saw were IEC C13.)

IEC 60320 specifies a maximum current of 10A for the C13/C14 connectors, and a maximum temp of 70C.
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Stop confusing the issue with facts and logic!

Scott Holtzman

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Re: Female nema receptacles powered boxes.
« Reply #38 on: October 23, 2014, 02:33:15 am »

BZZZT, wrong answer. To pick a nit, those were IEC receptacles, not NEMA, used in AT power supplies. (Well, maybe some very early ones had NEMA 5-15R, but all the ones I ever saw were IEC C13.)

IEC 60320 specifies a maximum current of 10A for the C13/C14 connectors, and a maximum temp of 70C.

You are picking the right nit, fingers got ahead of brain, yes standard c13/c14 connectors.  I don't recall if the convenience outlet had a rating stamped on the supply that might be lower than the connector.



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Scott AKA "Skyking" Holtzman

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ProSoundWeb Community

Re: Female nema receptacles powered boxes.
« Reply #38 on: October 23, 2014, 02:33:15 am »


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