UL approval

buy equipment that is UL approved. If you want to design it yourself you are looking at several $1000 to cover the cost of the approval process. rw

I'm designing a smart home system, which will need to be UL approved. I never gone through this before, and have some questions.

What does this involve ?

What are the lilkley costs ?

What considerations should i make in my design ?

What aspects will UL be mainly concerned with, ie, RF emmisions, High voltage saftey etc ?

Thanks,

Keith

Chris's suggestions are good but to more specifically answer your questions

UL is concerned with Safety - they have many different specifications targeted at different products. For electronics safety related to the primary power and to fire are the main considerations. Your design should us UL listed components for anything connected to the mains powers e.g. transformers, filter capacitor, terminal blocks, relays etc. You also have to pay attention to trace spacing on the pcb and the pcbs must be of flameproof material. Grounding, wire insulation and terminal spacing are also issues. In addition to submitting a unit and documents, UL will periodically inspect your manufacturing facility to insure that the product being manufactured matches the unit they inspected.

RF emissions requirements are governed by the FCC they require testing of any consumer electronic

Although the US doesn't have any requirement for electrical noise immunity, if I was designing a smart home system I would want design tested to the EU standards (CE) for impulse and RF noise withstand capability so the electrical noise would not mess up the operation and make it dumb house system.

If you are not designing hardware from scratch but are putting together a system from commercially available components, then I would make sure the units are UL, FCC and CE certified.

Dan