Difference Between 3 Terminal and 4 Terminal Solenoid

Updated 04/17/2018 | Published 04/14/2018

Products Featured in This Question

Starter Solenoid - SPST - 12 Volt - 100 Amp - Continuous Duty - Grounded

(13)

$33.90

Starter Solenoid - SPST - 24 Volt - 100 Amp - Continuous Duty - Insulated

(7)

$38.08

Question:

Working on aux charge solenoids on our camper. I find there are 2 types of solenoids, the 3 terminal and the 4 terminal type. I believer the 2 large terminals on both carry current from the charging location to additional batteries. If using the 3 terminal, the body of the solenoid is the ground with the small terminal wired to a power source to complete the circuit. With the solenoid with the 2 small terminals, one side is required to be the ground while the other is the power closing the circuit. Thanks for the help.

asked by: D G

Expert Reply:

You are correct. With a 3 terminal solenoid like the # PK5231201, the mounting hardware will serve as the ground connection. A 4 terminal solenoid like the # PK5232401 will require a dedicated ground wire from that additional terminal for this function.

When choosing between the two, I do recommend going with a 3 terminal like # PK5231201, as it simply eliminates the need for a separate ground wire, which will in turn require you to drill another hole into the trailer's frame.

expert reply by: Chris R