How an Electronic Rim Lock Is Fitted on a Metal Gate: Steps, Wiring and Tools

Short answer: an electronic rim lock is fitted on the inside face of a metal gate, usually on a welded mounting plate, with the key cylinder passing through the gate to the outside and the strike (keeper) fixed on the gate frame or post. A 2-core cable runs from the lock, across the hinge side, to a 12 V lock supply mounted indoors, and the supply then takes a remote, switch, app or door phone. Expect a fabricator for the plate, an electrician for the wiring, and about ₹3,049 to ₹5,499 for a ready kit on our store.

This guide walks through the fitting in order, with the tools you need and the mistakes that cause most call-backs. Facts about specific models come from their listings; prices are live website prices and include GST.

What do you need before you start?

Parts: an electronic rim lock, a 12 V lock supply or a kit that includes one, a push button if you want one, and cable. Kits such as Combo-CN59 and Combo-CN231 come with the lock, supply and remotes matched.

Tools:

• Measuring tape, marker and a spirit level
• Electric drill with metal bits, and a hole saw or step drill for the cylinder hole
• Hacksaw or cutter to trim the cylinder tail
• Screwdrivers and spanners
• Welding set (or a fabricator) for the mounting plate
• Multimeter to check voltage at the lock
• Conduit, flexible conduit for the hinge loop, cable ties and saddles

Which way does your gate open?

Check this first. Rim locks are fitted to suit whether the gate opens inward (towards the house) or outward (towards the road), and whether it hinges on the left or right. Some listings state this directly: the Combo-CN21 listing describes it for gates and metal doors that open outside, and the Combo-CN59 listing says its reversible latch fits left-hand and right-hand gates. If you are unsure, send a photo of the gate on WhatsApp before ordering.

How to fit an electronic rim lock on a metal gate

General steps. Follow the manual that comes with your lock, and use a trained electrician for the mains wiring.

1. Choose the height. Pick a comfortable hand height on the closing edge of the gate. The lock goes on the inside face; the strike goes on the frame or post, lined up with the latch.
2. Weld a mounting plate if needed. Many metal gates are made of hollow sections or open grille work, with nothing solid to screw into. The RML-8K listings say mounting on a metal gate may need welding of a plate. Weld a flat plate at the lock position, and a matching one on the frame for the strike if needed. Paint the welds against rust.
3. Mark and drill the cylinder hole. Hold the lock in place, mark the cylinder centre, and drill through the plate and gate to the size given in the lock's manual. The RML-8K uses a 32 mm brass key cylinder.
4. Fit and trim the cylinder. Push the cylinder in from outside with its ring, measure the gate thickness, and cut the tail so it engages the lock without binding. The RML-8K listing describes this step: fit the cylinder from outside, then cut the tail to suit the gate thickness.
5. Mount the lock. Fix the lock body and mounting plate with the screws supplied. Check that the key turns the lock smoothly before going further.
6. Fit the strike and align it. Close the gate slowly and check that the latch enters the strike cleanly without scraping. Adjust until the self-locking latch catches every time the gate shuts. A worn or bent strike can be replaced with the LH-RMLK latch holder.
7. Mount the supply indoors. Fix the lock supply on a dry wall inside the house, away from water and heat, as the kit listings advise.
8. Run the cable. Take a 2-core cable from the lock, along the gate to the hinge side, across the hinge in a loose loop of flexible conduit so it does not snap when the gate swings, then through conduit to the supply. Seal where it enters the wall.
9. Connect the wires. With the mains off, connect the lock to the supply's lock terminals, and any push button or door phone output to its input terminals, as shown in the wiring diagram.
10. Power on and test. Pair the remotes or set up the app, press to open, and check the gate locks again when it closes. Then test the key from outside.

How should the lock be wired to the supply?

• Lock to LOCK terminals. The RML-8K installation steps say to connect the lock to the LOCK terminals of your 12 V DC supply.
• Pulse, never continuous. The lock should get power only when opening. NavKar lock supplies give a short pulse; with Wi-Fi supplies, keep the Smart Life inching timer at 1 second, as the kit listings advise.
• Cable size for distance. A long, thin cable drops voltage and the lock may not release. Ask your electrician to choose the cable for the distance from the supply to the gate.
• Extra inputs. Supplies such as the PSRM-01 and PSWF-01 have terminals for a push-button exit switch and a video door phone's lock output.

For wiring a button on every floor, see how to open the gate lock from every floor. For a door phone, see how to connect an electronic lock to a video door phone.

Locks, kits and fitting parts (27 October 2026)

Product	What it is	Price
PSW-44 push button	Plastic exit push button, 86 x 86 mm, for opening from inside	₹217
LH-RMLK latch holder	Replacement latch holder and stopper for electronic rim locks	₹450
PSRM-01 remote supply	Remote lock supply with wired switch input. Lock not included	₹1,850
Secureye SC-S-200EL	Electronic rim lock, lock only, brass cylinder	₹2,450
Combo-CN21	Rim lock + switch power supply, for gates that open outside	₹2,700
PSWF-01 Wi-Fi supply	Wi-Fi lock supply with exit switch and door phone terminals. Lock not included	₹2,750
Combo-CN59	RML-8K lock + receiver + 12 V adapter + 3 remotes, reversible latch	₹3,049
Combo-CN231	RML-8K lock + PSRM-01 supply + 3 remotes	₹3,699
RML-8K lock only	Weatherproof 12 V DC rim lock with fitting kit and 8 keys	₹3,799
Combo-CN111	RML-8K lock + PSWF-01 Wi-Fi supply + 3 remotes	₹5,499

What are the common fitting mistakes?

• No plate on a hollow or grille gate. Screws pull out and the lock sags. Weld a plate.
• Cylinder tail left too long or cut too short. The key binds or does not engage. Measure the gate thickness first.
• Strike out of line. The gate has to be slammed to lock. Align it while the gate is hanging normally.
• Cable pinched at the hinge. It breaks after a few weeks of swinging. Leave a loose loop in flexible conduit.
• Supply outdoors. Water gets in. Keep it indoors on a dry wall.
• Lock left powered. The coil burns out. Keep the pulse short. If it has already happened, see electronic lock coil and latch replacement.

For the RML-8K and its kits in detail, read the RML-8K guide. Browse electronic rim locks and door lock power supplies and remote kits. Our team gives free wiring help on WhatsApp. Delivery across India is free and orders are prepaid.

FAQ

Do I need welding to fit an electronic lock on a metal gate?

Often, yes. The RML-8K listings say mounting on a metal gate may need welding of a plate, because hollow sections and grille gates have no solid surface for the screws.

Where should the power supply be mounted?

Indoors, on a dry wall away from water and heat. Only the lock goes on the gate.

Can I fit an electronic rim lock myself?

The mechanical fitting is within reach of a handy person with a fabricator's help for welding. The kit listings recommend a trained electrician for the wiring.

What cable is used between the lock and the supply?

A 2-core cable connects the lock to the supply's LOCK terminals. Choose a size suited to the distance so the lock gets its full 12 V; your electrician can advise.

How do I stop the cable breaking at the gate hinge?

Run it across the hinge in a loose loop of flexible conduit, so it bends gently each time the gate swings instead of being pinched.

Will the lock work if my gate opens inward?

Rim locks can suit inward or outward gates depending on the model. Check the listing, such as Combo-CN21 for gates that open outside or Combo-CN59 with its reversible latch, or ask us with a photo.

Prices are NavKar Systems website prices on 27 October 2026, inclusive of GST, and may change.