Hella Marine SPDT Mini Relay, 12V, 20/40A, 5-Pin, Dust Cover

Overview

The Hella Marine 933332051 is a 12V Mini ISO changeover relay (SPDT/Form C) rated for 40A continuous on the normally open circuit and 20A on the normally closed circuit at 85°C.

It is a straightforward way to switch higher-current accessories without running full load current through a small helm switch. On board, that often means deck and spreader lights, horns, washdown pumps, or other loads where keeping voltage drop down matters.

The relay uses five 6.3 mm blade terminals in the standard 30/87/87a (load) and 85/86 (coil) layout, and it includes a dust cover with an IP54 rating for basic splash and dust protection.

Key features

• 12V nominal coil with max coil voltage of 20V
• SPDT/Form C contacts with 40A continuous rating on N/O and 20A on N/C (at 85°C)
• Max inrush load rated to 150A for short startup surges
• Operate time = 10 ms and release time = 5 ms
• Ambient temperature range -40°C to +85°C
• Mini ISO footprint with 6.3 mm blade terminals for common 5-pin relay sockets
• IP54 dust cover to help keep spray and debris off the terminals in sheltered mounting spots

Installation and setup

Mount the relay in a dry, protected area such as behind the dash, inside a console, or in a covered locker. Use a properly sized fuse or breaker on the feed to terminal 30, and keep the high-current run as short as practical between the power source, relay, and load.

Terminal 87 is the normally open output, and 87a is the normally closed output. Terminals 85 and 86 are the coil connections that can be switched by a low-current control circuit.

This relay has no built-in coil suppression, so if the trigger circuit is connected to sensitive electronics, add the suppression method your system requires.

Compatibility and fit

This is a 12V relay, so it matches 12V DC boats and accessories. It uses the standard 5-terminal Mini ISO/SPDT layout with 6.3 mm blades, which keeps it compatible with many off-the-shelf relay bases and harness sockets. For longevity, avoid mounting locations that see regular washdowns or bilge water.

Use on board

It suits boats where a small switch or control output needs to command a heavier load, like spreader lights on a mast, deck floods on a hardtop, or an accessory circuit that you want switched from a protected control point. It is a practical fit when you need a changeover relay with a 40A normally open rating on a 12V system.

Orders are processed within 2 business days, which includes verification, packing, and dispatch. Orders of $100 or more qualify for free shipping when eligible. For orders under $100, shipping costs are calculated at checkout based on destination, package weight, and selected service. International shipping is available for eligible products, and certain items may require additional handling, warehouse transfers, or may ship directly from the manufacturer, which can affect processing time.

Deliveries are handled by preferred carriers such as USPS, UPS, FedEx, DHL, and others depending on your location and selected service. Estimated delivery times are displayed at checkout and may vary due to customs processing, carrier delays, weather, postal disruptions, or other circumstances beyond our control. Once your order ships, you'll receive a confirmation email with tracking information. Tracking may take up to 24 hours to update on the carrier's website and is also available through your account when applicable.

We ship throughout the United States and to most international destinations for products eligible for international shipping. International orders may be subject to customs duties, taxes, brokerage charges, or other import fees, which are the customer's responsibility and are not included in the product or shipping price. PO Boxes are accepted only when shipping through USPS, and not all packages qualify for this option. If your order does not arrive within the estimated delivery window, please contact us at info@apollolighting.com or +1 (954) 375-0100 so we can assist with locating your package.

Learn more.

Returns may be requested within 30 days of receiving your order. Items must be unused, uninstalled, unaltered, and returned in their original packaging with all tags, packing materials, blank warranty cards, manuals, instructions, accessories, and included items. Certain products, including installed or used electronics, electrical components, lighting, consumables, custom or special-order items, cut-to-length products, safety equipment, and merchandise exposed to water or marine conditions, may not be eligible for return.

To request a return, sign in to your account and select the applicable order and items, and submit your request for review. Eligible unfulfilled items may also be submitted for cancellation within 1 hour of placing the order. Returns or cancellations are not considered approved until you receive confirmation from Apollo Lighting. Please do not ship or drop off merchandise before receiving return approval and instructions.

Customers are responsible for arranging and paying for return shipping unless the return is due to an error by Apollo Lighting or the item is verified as defective, damaged, or incorrect. Missing, damaged, defective, or incorrect items must be reported within 2 business days of delivery, and photos or other documentation may be required for review. If the issue is verified, Apollo Lighting may provide or reimburse return shipping and issue a replacement or refund depending on the circumstances. International customers are responsible for return shipping, duties, taxes, customs charges, brokerage fees, and other costs associated with an international return.

After your return is received and inspected, approved refunds are issued to the original payment method and may take 5-7 business days to appear after processing. Original shipping and handling charges are nonrefundable, and the value of any included free items that are not returned may be deducted from the refund. Apollo Lighting does not charge a standard restocking fee on eligible returns. Returns that are incomplete, damaged, installed, used, altered, improperly packaged, or otherwise do not meet the eligibility requirements may be refused. We recommend using a trackable and appropriately insured shipping service for all customer-arranged returns.

For assistance, contact info@apollolighting.com or call +1 (954) 375-0100.

Learn more.

Many products sold by Apollo Lighting include a manufacturer's warranty covering defects in materials or workmanship. Warranty terms vary by brand, product category, and model, so eligibility, coverage duration, exclusions, and available remedies are determined by the applicable manufacturer. We recommend reviewing the warranty information provided with your product before installation or use, especially for marine electronics, navigation equipment, lighting, electrical systems, pumps, safety equipment, and other specialized marine products.

If you need warranty service, the claim must follow the process established by the manufacturer, authorized service center, or designated warranty provider. You may be asked for proof of purchase, a serial number, product registration, photos, maintenance or installation records, or other documentation. Apollo Lighting does not determine or modify a manufacturer's warranty coverage or final claim decision, but we are happy to help provide purchase information and direct you to the appropriate manufacturer or warranty resource.

Keep your receipt, product documentation, serial number information, and original packaging when practical. Damage caused by normal wear, misuse, improper installation, insufficient maintenance, corrosion, impact, unauthorized modifications, electrical issues, or operation outside the manufacturer's specifications may not be covered. Warranty claims are separate from standard returns, so a product that has been installed, used, or exposed to marine conditions may no longer qualify for return while still remaining eligible for evaluation under the manufacturer's applicable warranty.

Learn more.