NTE Electronics R04-11A30-120 Series R4 General Purpose Multicontact AC Open Frame Relay, Heavy Duty, DPDT Contact Arrangement, 30 Amp, 120 VAC

I bought this relay to use as an automatic transfer switch in my truck, to switch between shore power and the onboard inverter. I connected the inverter to the normally closed terminals, so it doesn't consume extra power to hold the relay on while using the battery. The shore power is connected to the normally open terminals as well as to the coil, so when external AC is connected, the inverter is disconnected. The common terminals go to a breaker panel in the truck. This relay seems solid and well constructed. I enclosed it in a plastic box (Amico 160mm x 110mm x 90mm Waterproof Plastic Enclosure Case DIY Junction Box), which fit it perfectly and had plenty of space for three #10-3 Romex cables (stranded boat wire; solid wire might be hard to bend in this confined space). I used crimp ring-tongue terminals to make all the connections.

I used this relay when I designed my own spa pump/temperature control unit. This relay works perfectly as the pump motor and the heating element together draws 24 amps. The unit is very sturdy and can handle high amperage start up loads. I can definitely see myself using the exact same relay some years from now when it reaches its life expectancy. As for now, my spa is running smoothly at a balmy 104 F.

Seems to work fine. I'm using it for a home-made transfer switch for a 3000W inverter to run a well-pump. Quiet and sturdy. I wanted to make a cover for it since it is open frame. I found the data-sheet at NTE's website has the full specs for the relay:http://www.nteinc.com/relay_web/pdf/R04.pdf

this is a sturdy, well built relay. i used it to make an auto-transfer switch for a friend's small bumper-pull travel trailer. it switches between a 2k watt inverter and a 120vac 15/20/30A RV pedestal. it has a constant duty rating.there is an audible click when it energizes, but relatively quiet, and there is no hum when energized. it's dimensions are approx 2.5x3.5x2" (LWH) but you'll need to allow a bit more room for wiring if installing in a tight space, eg., electrical box.it was perfect for this application.

I measured 34 mV of drop across the N.O. to common contacts with 13 amps following. This is quite acceptable and exceeded my expectations. I used this, as others have, for a so auto transfer switch for the shore line / inverter in the RV. Works great.

Item arrived as described but had to return it. Item arrived broken and unusable.

Great relay and sturdy but a bit overpriced served it purpose was small enough for me to manage to get it in my electric box here at the house to make an auto switch from solar to grid or grid to solar. The 120vac coil made it possible to not have the need in a conversion to 12 or 24v DC.So in short i made my own Auto Transfer Switch at 30 amps for 40 bucks and not 80.

Good Relay BAD shipping