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Different theatres provide different means for connecting equipment to be powered. Some simply provide a large number of standard edison style connectors, the same type used in homes. Others provide high-current (200 amps or greater) hookups, such as Cam-Lok type connectors, as shown in figure 7.2. Often some medium-capacity feeds are available, such as the MDS style feed. These medium-capacity hookups usually supply less than 100 amps, and are generally one or two phase. The type of hookup available in a venue dictates what type of equipment can be connected. Venues with high-current hookups can support portable lighting dimmers, large audio systems, and more. Venues with less capable hookups generally can not support large racks of dimmers or large audio systems.

**Figure 7.2:** Cam-Lok power connectors, often used to connect equipment to a venue's power feed. Cam-loks can carry very large amounts of current and provide a locking mechanism so the connectors will not come apart under normal conditions. Note the color-coded boots, used to differentiate between ground (green), neutral (white), and the three hot phases (black, red, blue).
$\begin{figure}\psfig{file=power/camlok1.eps,width=4in}\end{figure}$

Many venues provide some sort of combination of high-current and low-current hookups. WPI's Alden Hall is a prime example of this. The power panel in Alden Hall, shown in figure 7.3, provides a 200 ampere three-phase Cam-Lok feed, a 120 ampere two-phase MDS connection, as well as several 15 to 20 ampere edison and twist-lock outlets. The Alden house dimmer system, stage power outlets, and flown strip lights are also powered from this panel.

**Figure 7.3:** The power panel in WPI's Alden Hall. Several different types of power feeds are available from this panel.
$\begin{figure}\psfig{file=power/elect2.eps}\end{figure}$

Any venue that has been properly wired by a qualified electrician will have a circuit breaker panel that are used to shut circuits off in the event that they draw too much current. It is the current capacity of circuit breaker (in amperes) that determines how much current a circuit can supply. The breaker size is chosen relative to the type of cabling and connector used for the circuit, as each have different capacities. Circuit breaker panels provide a convenient means for manually turning circuits on and off. This can be a convenience and a safety feature, as it is much safer to connect power when the circuit is not live. For this reason, many larger feeds will have externally accessible power switches, as in the case of the Cam-Lok feed in Alden Hall at WPI.

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