Return to the Electrical Wiring Forum | Post a Follow-Up

wireless motion sensor and form C relay

Posted by hacksaw (My Page) on
Wed, Mar 23, 11 at 13:50

I'm seeking to connect a wireless motion sensor to my hard wired door bell chime. I see that many of the wireless motion sensor receivers have a form C dry contact relay with optional NO/NC positions. Being an "old timer" I'm only familiar with electromagnetic relays, can the door bell wire connect to this type of relay in the NO position? And if not does anyone make such a wireless motion sensor receiver combination that will run a hard wired door chime?

Follow-Up Postings:

RE: wireless motion sensor and form C relay

"Being an "old timer" I'm only familiar with electromagnetic relays..."

The output is a set of relay contacts.
"Dry contacts" means they are not mercury whetted and may have problems with low voltage (less than 5 V or so DC) or low current (less than 1 mA or so).
These are called 'dry circuit conditions.'

The typical 24 VAC on a doorbell is high enough voltage and the currents normally large enough (many 10s of mA minimum) to prevent dry circuit conditions from causing problems.

RE: wireless motion sensor and form C relay

Dry contacts means that no voltage is present at either terminal. It is designed to switch a seperate source of power

 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!

Return to the Electrical Wiring Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Please review our Rules of Play before posting.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.

Learn more about in-text links on this page here