Automotive Relay Panel SPST – All N.O. Contacts

(5 customer reviews)

$95.00$195.00 (USD)

Get ultimate control of your high-current devices. MGI’s most flexible modular relay panel is designed for easy installation.

  • Pre-wired with 3, 4, 6, or 8 SPST relays rated 40A
  • Built-in smart LED fuses that glow when blown
  • Comes with main feeder and main fuse
  • Easy to wire — Standard normally open (N.O.) operation
  • Each individual relay can be wired for either positive or negative switching
Clear All
    Reset options

    Protect your relays from flyback voltage when the power supply is suddenly disconnected. See What is a Flyback Diode? for more info.

    Choose your own fuse and feeder cable sizes. You can choose individual fuse sizes, between 5 - 40A. If the checkbox below is not selected, MGI will supply fuses and main feeder as follow:

     

    Our load size calculator automatically selects a larger main feeder conductor when necessary.

Description

High-Power Automotive Control
for when regular switches won’t work

Automotive Relay Panel SPST - All N.O. Contacts

FUNCTIONAL

Your high-power solution for when regular switches can’t handle high-current loads. Adding relays can become a complicated and messy project ⁠— our fused relay boxes provide centralized control and protection with minimal wiring involved. Ideal for all automotive devices such as spotlights, motors, pumps, and fans.

EASY INSTALLATION

Wiring is made easy. Each automotive relay box comes with a red main feeder cable and labeled screw terminals. Use the Installation Manual and wiring diagrams to help connect your power source, switches, and loads. It’s that easy.

RELIABLE

Quality is Guaranteed. Every automotive relay box is tested, with relays rated 40A at 12 volts to ensure optimal reliability come race time. What’s more, our relay boxes are built with GXL high temperature wire, and with no-nonsense screw terminal strips for reliable input and output wiring.

Modular Relay Panel Features
use our interactive builder to customize your multi-relay control module

Automotive Relay Panel SPST - All N.O. Contacts

Choose the Number of Relays

MGI modular relay panels are built with your choice of 3, 4, 6, or 8 relays. There’s no need for complicated and messy wiring — the SPST relays are pre-wired and ready to power your high-current devices. All you need to do is connect your switches and loads to the labeled screw terminal.

What’s more, every individual relay allows for negative switching, a unique feature among automotive relay panels. See the negative switching example for more details. Note: switches with LEDs cannot be used for negative switching.

But what makes an MGI relay panel truly special is our fused relays. Most fused relays are rated for 30A only — ours are uniquely manufactured to handle 40A. Every relay can also come with flyback diodes installed. The use of a diode in a relay circuit prevents voltage spikes from arising when the power supply is disconnected.

And yet with all these great features, MGI fused relay modules are remarkably lightweight due to their aluminum frame construction.

Choose Your Fuses

To make life easy, MGI relay panel modules come standard with pre-selected fuses for use with typical high-current devices. Want to choose your fuses instead? MGI’s interactive fuse selector makes it easy to order the relay panel you need. You can also input your loads — we use industry standard, tried-and-true formulas to provide recommended fuse and feeder sizes for your custom loads.

  1. Simply enter your current load for each relay into the calculator
  2. and indicate whether it is a motor load.
Number of Relays
Main Fuse
Feeder Cable
Automotive Relay Panel SPST - All N.O. Contacts

Modular Relay Panel Wiring Diagrams
how to install 3, 4, 6, and 8 relay modules

STEP 1

Battery Power

relay box power

Connect the red main feeder conductor to the car starter’s battery power terminal. Then, install the supplied main fuse and holder in the main feeder conductor between the starter and the power stud found inside the panel.

STEP 2

Switches & Grounds

relay switches

Install a ground wire between the relay panel and the auto chassis. Then, connect the control circuit terminal to your switch inputs, with switch outputs connected to the appropriate screw terminals.

STEP 3

Outgoing loads

relay box wiring

Connect your loads to the appropriate screw terminals. Ground your loads. See the 3, 4, 6, and 8 relay module diagrams above.

WHAT’S INCLUDED
what comes with every SPST automotive relay panel kit

  • Aluminum frame module and your choice of 3, 4, 6, or 8 built-in relays
    • 40 Amp SPST relays
    • Integrated fuses
  • Integrated LED blade fuses (+ spares)
    • ATC / ATO style blade fuse with LED light that glows when blown
    • Available in sizes 5 to 40A
  • 5A LED control circuit fuse (+ spare)
  • Main fuse & fuse holder
    • Mini ANL bolt-down fuse
    • Available in sizes up to 150A
  • 5′ main feeder conductor
    • Available in sizes up to #2 AWG
  • ½” strain relief cable gland(s)

FREQUENTLY ASKED QUESTIONS
Answers to Popular questions

Why buy a fuse & relay panel?

When rebuilding, restoring, or refurbishing your vehicle, you’re bound to need electric pumps, fans, spotlights and more. These high-current devices will damage regular ignition key switches or low-current switch panels — however, an electromagnetic switching relay panel will give you the safe and reliable control you need.

Automotive Relay Panel SPST - All N.O. Contacts

Can this relay box operate “normally closed” devices?

No. Our SPST relay boxes are designed for standard normally open (N.O.) loads only. However, our specialty SPDT Bosch style relay boxes can power devices that are normally closed.

Automotive Relay Panel SPST - All N.O. Contacts

WIRING EXAMPLES
some popular relay panel projects

Negative Switching

Some devices are designed specifically for negative ground switching. With our SPST relay panels, every individual relay allows for negative switching. Simply connect your switch between the appropriate ground terminal and chassis. Note: switches with LEDs will not function properly with negative switching.

Dimensions

Relay Box Specs
without feeder, fuses, and main fuse holder

Physical Dimensions (L x W x H)
4.5" x 3.50" x 3.25"
Weight
14 oz

4 Relay Box — RCP3-GEN3

Physical Dimensions (L x W x H)
5.625" x 3.50" x 3.25"
Weight
18 oz

4 Relay Box — RCP4-GEN3

Physical Dimensions (L x W x H)
6.25" x 4.5" x 3.25"
Weight
28 oz

6 Relay Box — RCP6-GEN3

Physical Dimensions (L x W x H)
6.625" x 5.625" x 3.25"
Weight
36 oz

8 Relay Box — RCP8-GEN3

All dimensions and weights are supplied as general information only and are not certified.

5 reviews for Automotive Relay Panel SPST – All N.O. Contacts

  1. Keith Conner (store manager)

    Made my life alot easier wiring spotlights on my truck. Saved me the hassle of wiring relays all over the place.

  2. paisleyrowley (store manager)

    works like a charm. glad its made of metal.

  3. Kelsi (store manager)

    Great price and comes with everything you need. This kit came with everything I needed and was easy to install.

  4. carlton.calhoun122 (store manager)

    thumbs up

  5. Don Knight (verified owner)

Thank you for leaving a review!

Before finalizing your purchase

It is important to familiarize yourself with the MGI panel Installation Manual. Not only does this help you to select the appropriate options for your race panel, it will enable you to tackle any troubleshooting issues with confidence.