Relay advice needed


  #1  
Old 01-06-22, 11:26 AM
M
Member
Thread Starter
Join Date: Jan 2022
Posts: 2
Received 0 Upvotes on 0 Posts
Relay advice needed

This is my first post. I'm not an electrician but I'm familiar with home wiring and have built my own amateur radio stations since 1970. I know how relays work but have never used or wired them and the local electrical supply stores have not been able to answer my question.
  • I have four 120vac front yard lights controlled by a switch on one circuit and five 120vac back yard lights controlled by a switch on a different circuit (same or different phase not currently known).
  • I need to add 120vac side yard lights that will turn on if either or both existing switches are on. Motion sensor won't work here and I do not want to wire in a separate 3-way switch.
  • I created the attached circuit diagram that powers the side lights from the circuit that powers the back yard llights but uses a relay to bypass the switch controlling the back yard lights when the switch controlling the front yard lights is on.
    • Instead of taking a single hot wire as input and routing or switching between two outputs, the NO and NC are connected to switched and unswitched hot wire inputs with a single output powering the lights.
  • I have several questions:
    • Are there any objections to the circuit design? I know that turning the circuit 2 switch on or off while the circuit 1 switch is on may cause the side lights to flash briefly when the relay switches but I have no problem with that.
    • Is there a relay that will function in this manner and, if so, what is the type or description of the relay?
    • If it is allowed in this forum, would a particular make/model of relay be recommended?
    • Would the elay wiring involve anything other than connecting the inputs to the NO and NC terminals and connecting the lights to the normal relay input terminal?
Thanks in advance for any advice you can give me.

​​​​​​​
 

Top Answer

 
01-06-22, 01:09 PM
PJmax's Avatar
PJmax
PJmax is offline
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 64,590
Received 3,880 Upvotes on 3,477 Posts
Welcome to the forums.

In addition to Johns help there is a perfect relay for that application. It's called a RIB relay.
You're only connecting two lights so either model would be able to handle that load.

20A RIB relay
10A RIB relay


You'll cap off un-needed wires.
 
  #2  
Old 01-06-22, 11:49 AM
2
Member
Join Date: Jan 2014
Location: USA near Boston, MA
Posts: 2,240
Received 387 Upvotes on 337 Posts
Your diagram looks fine. Any relay with a 120 Vac coil and contacts rated 15 or 20 A or higher at 120 Vac or higher will work. The relay should be mounted in an enclosure with proper wiring connections for 120 Vac use.

If the lighting circuits are on different phases you should post a warning at the relay box stating that 220 volt exposure is there. Include the circuit numbers in disconnect instructions.
 
MBailey voted this post useful.
  #3  
Old 01-06-22, 01:09 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 64,590
Received 3,880 Upvotes on 3,477 Posts
Welcome to the forums.

In addition to Johns help there is a perfect relay for that application. It's called a RIB relay.
You're only connecting two lights so either model would be able to handle that load.

20A RIB relay
10A RIB relay


You'll cap off un-needed wires.
 
2john02458, MBailey voted this post useful.
  #4  
Old 01-06-22, 02:37 PM
M
Member
Thread Starter
Join Date: Jan 2022
Posts: 2
Received 0 Upvotes on 0 Posts
John and PJ - Thank you both for your assistance and I'll pick up a RIB relay. I just verified that the circuits have the same phase but I'm putting a detailed explanation of the wiring and purpose in the relay box.
 
  #5  
Old 01-06-22, 02:44 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 64,590
Received 3,880 Upvotes on 3,477 Posts
With the use of a relay.... you aren't concerned with phase or different circuits.
The relay will isolate the two completely.
 
I Mullins voted this post useful.
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: