<html>
<head>
<meta content="text/html; charset=windows-1252"
http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
<div class="moz-cite-prefix">I have always used a 50% assumption.
Then divide by 3, assuming you're using a 3-phase 5-wire feeder.
Then assume you want a somewhat standard size - in your case, 600A
3-phase. We have a 300A 3-phase for 176 2.4K dimmers, and have
never even come close. I'm not sure I would have room to hang
enough fixtures to load the system fully.<br>
<br>
Patrick<br>
<br>
On 2/11/2015 12:06 PM, Dougherty, Jim via Stagecraft wrote:<br>
</div>
<blockquote cite="mid:D100F638.11E88%25jdougher@middlebury.edu"
type="cite">
<meta http-equiv="Content-Type" content="text/html;
charset=windows-1252">
<div>When looking at a lighting system (particularly in the
context of a new or replacement installation), is there a
formula used to calculate a systems lighting load? For example,
assume an installation has 200 2.4K dimmers. To size the service
at 4000A to handle the load if the system were to be run
entirely at full is ridiculous. How is it, then,
designed/specified? Based on a percentage of that maximum?
Taking into account a typical or perhaps maximum instrument
count from past shows, and applying a formula to that number
based on the assumption that no plot’s lights are all on at
once? Darts and a Square D catalog?</div>
<div><br>
</div>
<div>Ideally I’m looking for a reference based on manufacturer’s
requirements, NEC, industry standard, etc. Rule of thumb is
definitely welcome but not as helpful in this context. I find
it interesting that the load will presumably be diminishing over
time as our industry gradually shifts to a greater reliance on
LED and other lower-load fixtures. Our own system will be a mix
of conventional and LED for a long time to come.</div>
<div><br>
</div>
<div>Thanks.</div>
<div><br>
</div>
<div>- Jim Dougherty</div>
<div>ATD, Middlebury College Theatre Dept.</div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
<pre wrap="">____________________________________________________________
For list information see <a class="moz-txt-link-rfc2396E" href="http://stagecraft.theprices.net/"><http://stagecraft.theprices.net/></a>
Stagecraft mailing list
<a class="moz-txt-link-abbreviated" href="mailto:Stagecraft@theatrical.net">Stagecraft@theatrical.net</a>
<a class="moz-txt-link-freetext" href="http://theatrical.net/mailman/listinfo/stagecraft_theatrical.net">http://theatrical.net/mailman/listinfo/stagecraft_theatrical.net</a>
</pre>
</blockquote>
<br>
<br>
<pre class="moz-signature" cols="72">--
G. Patrick McCreary
Technical Director
Department of Theater and Dance
Indiana University of Pennsylvania</pre>
</body>
</html>