How to wire a 4 pin relay

1. How is a 4 pin relay wired?
2. What is 85 and 86 on a relay?
3. What is 87a on a relay used for?

How is a 4 pin relay wired?

4 Pin Relay

4 pin relays use 2 pins (85 & 86) to control the coil and 2 pins (30 & 87) which switch power on a single circuit. There are 2 types of 4 pin relay available; normally open or normally closed. A normally open relay will switch power ON for a circuit when the coil is activated.

What is 85 and 86 on a relay?

85 and 86 are the coil pins while 30, 87, and 87a are the switch pins. 87 and 87a are the two contacts to which 30 will connect. If the coil is not activated, 30 will always be connected to 87a. You can think of this as the switch in OFF.

What is 87a on a relay used for?

One of these will be used to ground your current, while the other will be connected to a switched power source. 87 and/or 87a will be connected to your controlled accessories that you wish to turn on and off with your relay. 30 will then be the pin connected to your battery power.