4.2 Load

The best recommendation is to use one control per luminaire. Next best is to have a control run a contactor (or relay) that operates multiple luminaires. If you must operate two or more HID fixtures from one control, the total ballast starting current or operating current must not exceed the control rating, usually 15 amps or 1800 VA for twistlocks and 1000 VA for buttons.

Remember: It is ballast volt amperes (VA), not lamp wattages, that are additive in multiple luminaire systems.

For example, a GE Lighting catalogue lists the starting current on one 400 watt, 120VAC mercury vapor fixture as 10.8 amps (1296 VA) and operating current as 7.3 amps (876 VA). Operating two of these fixtures on one control would dramatically reduce control life since the combined starting load would be about 2600 VA (1296VA X 2 = 2592VA) on an 1800 VA rated control.

4.3 Handling

Photocontrols need to be rugged. Normal shipping, warehousing and occasional rides in a bucket truck should not do any harm. However, all controls are NOT equal. Unless you specify drop resistance, you might not get it. Photocontrol specifications should include the following:

Control must withstand a 3 foot (0.9 meter) drop to a concrete floor and still function to all specifications.

Photocontrols should be stored in their original boxes until ready to be installed. They are rain proof when installed or stored with the legs down. Controls are not rainproof if stored legs up and exposed to rain. This may seem like redundant advice but pre-installation water damage has been a problem, particularly in tropical and sub-tropical places were controls are left exposed on the truck or loading dock during rainstorms.