40A NO-NC Relay

$13.00

(1 customer review)

Sealed, Watertight Relay

Rated at: 30A on the NC (Normally Closed) circuit, 40A on the NO (Normally Open) circuit

Features waterproof cap with seal, as well as waterproof leads

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SKU: 100002 Categories: ,
Frequently bought together
marine grade positive electrical stud
negative stainless stud marine grade
Current item: 40A NO-NC Relay $13.00 $13.00
1 × Positive Stud $18.00
1 × Negative Stud $18.00

Product Description

40A NO-NC Relay

This sealed, watertight relay is a great choice for several situations you may find yourself in when working on your boat’s electrical system.

It’s a full NC / NO relay – Rated at 30A on the NC circuit, and at 40A on the NO circuit. It has a 12V coil, which means it’s meant to be switched by a controller than operates on 12V.

The NO (Normally Open) circuit (blue) is one that is always off (an open circuit is off), unless a +12V is applied to the coil. This would be used when you have a switch that is not rated for the current load of the device.

For example:

Let’s say you’re using a 10A pushbutton switch, but want to turn on a light bar that requires a 30A fuse. The NC (Normally Closed) circuit (yellow) – and this is pretty cool – “flip-flops” what the control switch is doing.

So, when the switch is ON… the relay is OFF (open). And when the switch is OFF, this circuit of the relay is ON (closed).

This is needed on things like KILL switches on a diesel engine, where the fuel pump needs a constant flow of 12V until you’re ready to shut it off; at which time that 12V signal is deprived, starving the engine to stall.

This 40A NO-NC relay is nice to use in wet environments, because it has a nice waterproof cap with seal – and waterproof wire leads. The wire leads include (2) 16AWG and (3) 12AWG. Connecting these leads with heat shrink butt connectors should make a complete waterproof assembly.

Wiring Diagram:

40A NO-NC Relay Wiring Diagram

1 review for 40A NO-NC Relay

  1. Chris Rapach (verified owner)

    They are amazing ! It makes wiring a boat so much easier when you can label a bunch of wires and run them all at the same time and know what wire goes to what when you get it ran threw the boat.

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