Low Voltage keypads

[stepke]

Hi,

this is my first thread in this great forum. Maybe someone can give some information to following question: A customer of mine wants to install a home automation system in the US. This is a bus system runs with max 30VDC/ max 15 mA on the bus site between switches - called keypads - and so called actuators. All the actuators are UL listed, because they switch the load. What`s with the keypads? I haven?t found anywhere some paperworks where it`s told what is required to such keypads. Does anybody know if there is something special to consider? For example fire safety, special installation boxes or certifications.

Thanks for answering

Stepke

 

[hbiss]

My opinion is that the keypads should also be UL (or other lab) listed as should the low voltage power source. The power source listing will determine what the wiring requirements are. If the power source is limited to supplying 30vdc at 15ma as you say then certainly CL2 wiring could be used. It is the power source that determines this, not the switches, keypads or load. You could have a power source that is capable of supplying say 30vdc at 20 amps and even if it supplied a device that only drew 15ma, the wiring requirement would be much more restrictive.

-Hal

 

[stepke]

Hi Hal,

thanks for your answer. I agree with you, that it depends of the power supply. In this case the power supply for the whole homeautomation system is a PELV 28V-31V DC by 640mA. This power supply can feed max. 64 devices on the low voltage bus part. The bus part is completly seperated from the load part. Can this be the reason, that i can`t find requirements related to certifications for such keypads?

Stepke

 

[stepke]

My opinion is that the keypads should also be UL (or other lab) listed as should the low voltage power source. The power source listing will determine what the wiring requirements are. If the power source is limited to supplying 30vdc at 15ma as you say then certainly CL2 wiring could be used. It is the power source that determines this, not the switches, keypads or load. You could have a power source that is capable of supplying say 30vdc at 20 amps and even if it supplied a device that only drew 15ma, the wiring requirement would be much more restrictive.

-Hal

Hi Hal,

thanks for your answer. I agree with you, that is depends on the power supply. The whole homeautomation system works with a power supply 29V - 31V 640mA. The secondary output is ELVP. The power supply feeds 64 Bus devices. Bus system and load wires are completly seperated systems. Is it possible that i can`t find any paperworks because the keypads are supplied from a ELVP Power supply? I heard, that the inspector just looks at the 110V and not at the low voltage installation !?

Stepke