← All lessonsHow to read a lighting-control spec sheet
In short: Read voltage, including any multi-voltage range, then protocol, load rating, and the safety listing. If those do not match the circuit, skip the rest of the sheet.
What to look for
- Voltage, including a multi-voltage mark. MVOLT and similar marks mean the device accepts more than one line voltage, often a range such as 120 through 277. Read the range printed next to the mark. It is not a promise of every voltage, and a single-voltage part fails on the wrong circuit.
- Protocol. 0–10V is an analog pair that dims a group together. DALI is a digital bus that can address individual fixtures and report back. BACnet is a building-automation network protocol. Line-voltage and low-voltage switch circuits are different again. The control and the load have to speak the same one.
- Load type and rating. A wattage figure for incandescent or resistive loads is not the same as a rating for LED drivers or electronic ballasts. Inrush can be many times the running current for a fraction of a millisecond. Match the load type the sheet actually names.
- How much the output can drive. On 0–10V, that is the current the interface can source or sink, and whether it sinks or sources. On a relay, it is the contact rating and how many drivers you will land on it. One output for a whole floor is how contacts get overloaded.
- Listing and environment. Look for a safety listing that matches where the device will be installed, and for a separate emergency listing if the circuit is emergency. Indoor dry, damp, and wet are not interchangeable. A general lighting listing does not cover an emergency unit.
- What the box is. A wall dimmer, a panel relay, a driver, and a room controller can share a family name and still be different parts. Confirm the form, the line voltage, and the control wiring before comparing anything else on the sheet.
Common mistakes
- Reading a multi-voltage mark as every voltage in the building, instead of the range printed beside it.
- Mixing 0–10V, DALI, and BACnet parts because they are all lighting controls.
- Sizing from steady LED watts and skipping the LED or ballast rating and the inrush.
- Ignoring sink versus source, or the number of drivers a 0–10V output can feed.
- Using a normal-control listing as permission to put the part on an emergency circuit.
- Buying from the product-family name and skipping voltage, protocol, and load.
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General buying advice only. This guide does not speak for any manufacturer, and it names no brands or part numbers. The shop is separate.
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