Product Description

12V 50A/40A NO/NC Relay

This sealed relay is great for the harsh boating environment.  It’s used in applications where you need to switch a higher current load than the switch is rated for.  It also has a Normally Closed (NC) circuit.  An NC circuit is used when you want power to be delivered to the device all the time EXCEPT when you press the switch.  Basically “flip-flopping” the switch’s output.

This is a NC / NO relay – Rated at 40A on the NC circuit, and at 50A on the NO circuit. This waterproof relay has a 12V coil and contacts, which means it’s meant to be switched by 12V switch, and will switch a 12V (nominal) line.

The NO (Normally Open) circuit (87 Terminal) is one that is always off (an open circuit is off), unless a +12V is applied to the coil (86 terminal). 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 5A small toggle switch, but want to turn on a high capacity pump that requires a 40A fuse.

The NC (Normally Closed) circuit (87a Terminal) is useful because – 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).  If you don’t need this circuit, then simple don’t connect it.

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 relay is nice to use in wet environments, because the case is sealed with potting compound where it connects with the base .  The terminals are all 0.250″ Quick Connects which we also sell.

Manufacturer: Picker

P/N: PC792E-1C-C1-12S-DN-X

We also carry a waterproof relay with similar circuitry in a sealed case with wire leads here.