Theatre Entertainment Panel Ratings

[barefootbryan2335]

I am the tech director at a community theatre . We have conventional fixtures hooked to shoebox dimmers that are powered by the a 240V 200 Amp electric panel.

My first question is how many Amps can be drawn from the electric panel on each leg? Does each leg supply 200 Amps or 100 amps from the box on the branch lighting circuits? This electric panel only supplies 120 Volt, 20 Amp lighting circuits. It seems to me that the total Amperage from the panel should be 400 Amps and that theoretically the neutral would have 0 Amps on it with a properly balanced load.

It is my understanding that in the code it allows for 100% maximum usage of the Amperage in the panel if it is used for entertainment and less than three hours use at a time. Is this correct?

It is my understanding that a 20 Amp branch can carry the full load if used under three hours (supplying a shoebox dimmer). Further, I thought that in the entertainment section of the code, it states you can use a conventional 15A plug to connect the shoebox dimmer to the 20 Amp branch circuit instead of a 20 Amp plug. Is this correct?

 

[n1ist]

Keep in mind that most shoebox dimmers (ADJ, DMX4, etc) have severely underrated components - 6A triacs, a 10A switch, and some with a 16AWG cordset. Unless you are using Leprecons, I wouldn't load them to more than 575W per channel, and only 3 of the 4 channels on at a time. As for the 20A circuits, as long as they have 2 or more receptacles (ie. one or more duplex), they can take 15A plugs (with a 15A or less load, of course...)
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[JFletcher]

Welcome. Answers in red.

I am the tech director at a community theatre . We have conventional fixtures hooked to shoebox dimmers that are powered by the a 240V 200 Amp electric panel.

My first question is how many Amps can be drawn from the electric panel on each leg? Does each leg supply 200 Amps or 100 amps from the box on the branch lighting circuits? 200AThis electric panel only supplies 120 Volt, 20 Amp lighting circuits. It seems to me that the total Amperage from the panel should be 400 Amps and that theoretically the neutral would have 0 Amps on it with a properly balanced load. Yes, a perfectly balanced split phase 240V panel will have 0 amps on the neutral.

It is my understanding that in the code it allows for 100% maximum usage of the Amperage in the panel if it is used for entertainment and less than three hours use at a time. Is this correct? Yes

It is my understanding that a 20 Amp branch can carry the full load if used under three hours (supplying a shoebox dimmer). Yes. Further, I thought that in the entertainment section of the code, huh? it states you can use a conventional 15A plug to connect the shoebox dimmer to the 20 Amp branch circuit instead of a 20 Amp plug. Is this correct?Yes, you can use a 5-15 plug on a 6-15 receptacle

No idea what "entertainment section of the code" is. Any non-heating load that runs less than three hours is non-continuous. Typically lighting loads are continuous; if so, you can only load the branch circuits to 80% of their breaker rating.

 

[GoldDigger]

I am the tech director at a community theatre . We have conventional fixtures hooked to shoebox dimmers that are powered by the a 240V 200 Amp electric panel.

My first question is how many Amps can be drawn from the electric panel on each leg? Does each leg supply 200 Amps or 100 amps from the box on the branch lighting circuits? This electric panel only supplies 120 Volt, 20 Amp lighting circuits. It seems to me that the total Amperage from the panel should be 400 Amps and that theoretically the neutral would have 0 Amps on it with a properly balanced load.

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It is a 200A panel, which means that it can equally well supply 200A of 240V, line to line, load OR two sets of 120V line to neutral loads each adding up to 200A. As you note, in either case the neutral current is zero. The worst case neutral current would be if for some reason only the 120V loads connected to one of the lines is active. The neutral current in that case would be equal to the line current on that line.

 

[dkidd]

If the dimmers have harmonic content, the neutral current might not be zero.

 

[gadfly56]

Welcome. Answers in red.




No idea what "entertainment section of the code" is. Any non-heating load that runs less than three hours is non-continuous. Typically lighting loads are continuous; if so, you can only load the branch circuits to 80% of their breaker rating.

Section 520: Theaters, Audience Areas of Motion Picture and Television Studios, Performance Areas, and Similar Locations.