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Are there any guidelines?

Do the guidelines differ depending on resistive/inductive/reactive loads?

For example, the Vishay VO2223A is rated up to 1A. At 110V it seems it can switch up to a 1 A x 110V = 110 watt load. I saw some training material that indicated only up 22W load. Is this derating for safety? Is it to cover startup current draws?

I'd like to independently switch several AC devices: 50W heater, 23W CFL, 4W water pump.

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The Vishay VO2223A you gave a link to is not a solid state relay but a optically isolated triac... Is this a question about the vishay or solid state relays? – Kit Scuzz Nov 12 '12 at 7:59
Thanks. I'd be interested in the answer to both, though if I had to pick one, I'd say Vishay. – Brian Low Nov 12 '12 at 8:19
Could you perhaps describe what you're trying to do? The two questions aren't terribly related... solid-state relays and triacs aren't the same thing, so the answer to "both" questions is very different. – Kit Scuzz Nov 12 '12 at 10:07
Edited question to provide more info. – Brian Low Nov 12 '12 at 21:08

It's a typical derating commonly used in various industries. Primarily to ensure long term reliability. And yes, that particular component can be referred to as a solid state relay.

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What is a good guideline for derating? In this case max load = 25% of rated load? – Brian Low Nov 24 '12 at 19:29

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