How much power does your rig take? What about various components of lighting? Do you know the average and peak amp draws?
If you don’t, it’s time you learn! Every room has a different electrical layout. Some have independent outlets and some have a “quadrant” system. Some are 15amp, some 20amp, and some just plain suck and trip everytime someone sneezes.
Knowing your amperage draw also saves your client money; Let’s say that you are doing a prom and the hotel charges for power drops. You ask for 4 20amp circuits but you only needed two. The school winds up paying TWICE as much for power that you don’t need. Anything you can do to save the client money will make you look that much better.
So how do you calculate amperage? Some lights tell you the power draw on the back (not to be confused with fuse rating), but even then it can get pretty darn inaccurate. A quick calculation also yields a rough explanation of what the amperage is (the AMount of power being used):
W/V = A. Basically, you take the wattage draw, divide by voltage available, and you get amperage! Sounds easy, right? The problem lies that a 600W amp pulls MORE than 600W of power, and a 250W light has motors, fans and other power-sucking doo-dads. You also need to realize that not every venue has the same voltage coming out of the outlets; you’ll find various voltages from 110V to 120V. This affects your math greatly!
But wait, there’s more! If you use a long extension cord, the voltage drops depending on the length and gauge of the run.
ARGH! If only there was some easy way! Well, of course there is. Head over to Lowe’s and pickup Kill-A-Watt. The device is simple to use: plug your load into it and it will tell you the amperage draw. This device is SUPER easy to use and EVERY DJ/production company should own one (or two).
This will put you in full control of your power draw, alongside a circuit sniffer (more on that later). Here are some tips when it comes to power draw:
*Remember that you don’t want to maximize your load; give yourself 10-20% headroom, so you have 16-18amp draw on a 20 amp circuit.
Several power conditioners, surge protectors, etc only handle a 15AMP load.
*Most ballrooms and venues *should* use 20AMP breakers, but unless you see those IN PERSON, assume they’re 15!
*Buy a circuit sniffer! This handy tool allows you to match paired outlets. Never take anyone’s word about what circuits are separate UNLESS they’re an electrician.
*Thin gauges of cable can cause weird effects (as can load-heavy devices). For example, if you run subs and black lights in the same circuit, you’ll notice that the black lights flicker to the beat.
I can proudly say that by practicing these techniques, and taking careful notes on each venue, I’ve yet to trip a breaker. After all, nothing is more embarrassing! So go pick up a KIll-A-Watt and arm yourself with the best tool ever!
Filed Under: Lighting, Sound
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