LTL Controls MASTER Lighting Relay Controllers w/o Timer (120V & 240V Universal Plug) – 4 Light

The LTL Controls MASTER 4-Light Relay Controller is a dedicated power-management hub for HID grow-room setups running up to four lights. It handles a maximum load of four 1000W ballasts, operates on both 120V and 240V power through a universal plug, and switches the load through a robust 30-amp relay. A 120V trigger cable is included so the controller integrates directly with any standard 120V timing device — no rewiring the ballasts themselves.

LTL Controls MASTER 4-Light Relay Controller Specifications

All specifications below are drawn from the manufacturer’s canonical product data for the MASTER 4 variant.

Specification	Value
Model	LTL Controls MASTER 4
Controlled Lights	Up to 4 HID lights
Maximum Ballast Load	4 × 1000W (4000W total)
Input Voltage	120V & 240V
Plug Type	Universal plug (120V & 240V)
Maximum Relay Amperage	30A
Trigger Cable	120V trigger cable included
Timer	Not included (w/o timer)
Weight	5 lb

Why Choose the LTL Controls MASTER 4-Light Relay Controller

Relay controllers serve a specific function in an HID grow room: they let a low-power timer or environmental controller switch on and off high-amperage ballast circuits without directly handling that current. The MASTER 4 is built around this separation of control and load.

The unit accepts both 120V and 240V through a universal plug, which means you do not need a separate 240V-only or 120V-only version depending on how your room is wired. If you are running 240V ballasts in one facility and 120V in another, a single MASTER 4 covers both configurations. This is practically useful for growers who move equipment between locations or who are upgrading their room voltage over time.

The 30-amp relay rating on the MASTER 4 provides meaningful headroom when running four 1000W HID ballasts. A 1000W HPS ballast typically draws around 9–10 amps at 120V or approximately 4.5–5 amps at 240V per unit. Four ballasts at 120V represent roughly 36–40 amps of draw — which means the MASTER 4 is rated for a 240V four-light setup but may require load balancing or a step-up to the MASTER 8 for full 120V four-ballast operation. Review your specific ballast draw against the 30A relay limit before wiring.

The included 120V trigger cable integrates with any standard 120V timer or environmental controller. You keep your existing timer and simply run the trigger cable to the MASTER 4 — the timer switches a small current, and the relay switches the ballast circuit. This approach also means the high-current wiring stays at the ballasts and the controller, reducing the number of connections in the circuit.

• Controls up to four HID lights from a single relay unit, reducing the number of separate outlet strips or timer connections in the room
• Dual-voltage universal plug accommodates both 120V and 240V circuits without buying a different product for each
• 30A relay rated for heavy ballast loads at 240V operation
• 120V trigger cable allows integration with any standard mechanical or digital timer
• Isolates the high-current ballast circuit from the low-voltage timing signal, reducing wear on timers and environmental controllers

Best Uses for the LTL Controls MASTER 4-Light Relay Controller

The MASTER 4 is most useful in rooms where you have multiple HID ballasts that need to be switched on the same schedule, and you want a single relay point rather than individual outlet timer connections for each light.

• Dedicated HID flowering rooms: A four-light 1000W HPS setup is a common configuration for mid-size indoor production. The MASTER 4 consolidates the switching for all four lights into a single controlled relay, with only the trigger cable connecting to your timer.
• Rooms using a separate environmental controller: Environmental controllers such as CO2 generators, dehumidifiers, and multi-zone timers often output a 120V signal to trigger external loads. The MASTER 4 accepts that 120V trigger directly, so you can include your lighting in the controller’s schedule without running the full ballast current through the controller itself.
• Mixed-voltage facilities: Grows that use 240V ballasts for efficiency but have 120V control circuits benefit from the universal plug design. The relay operates at the ballast voltage while the trigger cable operates at 120V regardless.
• Expanding existing relay setups: If you already use an 8-light relay controller for a larger room and need a separate controller for an adjacent propagation or veg space with fewer lights, the MASTER 4 provides the same relay-based switching at the appropriate scale.

For rooms running more than four lights, the MASTER 8 variant controls up to eight 1000W ballasts through a 50-amp relay and uses the same trigger cable design. If you are configuring a larger operation, also consider pairing this controller with a high-output LED fixture for supplemental or full-cycle lighting alongside your HID setup.

LTL Controls MASTER 4 vs Similar Relay Controllers

HID relay controllers at this price point generally fall into two categories: simple outlet-based relay strips that handle one or two lights per unit, and dedicated multi-light relay controllers like the MASTER series that manage four or eight lights through a single relay and a standardized trigger input.

Single-outlet relay switches offer low upfront cost but multiply your timer connections as you add lights — each light needs its own switched outlet, and each timer connection is a potential failure point. The MASTER 4 consolidates four channels into one relay, so a single timer or controller signal manages the entire four-light bank.

The MASTER 4 does not include an integrated timer, which is by design. Many growers already have a preferred timer or environmental controller. The “w/o timer” configuration means you are not paying for a second timer and not forced to use one built-in timer when your existing controller offers more features. If you need a built-in timer, LTL Controls offers timer-included variants — the w/o timer version is specifically for growers integrating with existing control systems.

The MASTER 8 variant uses the same relay architecture at larger scale: up to eight lights and a 50-amp relay. If your room is likely to grow beyond four lights, factor in the MASTER 8 pricing before committing to two MASTER 4 units, as a single MASTER 8 may be more cost-effective and simpler to wire.

For rooms transitioning from HID to LED, note that many LED drivers have different switching characteristics than magnetic or digital HID ballasts. Verify your LED driver is compatible with a relay-based controller before purchasing.

Compatibility

The MASTER 4 is designed for use with HID lighting systems: high-pressure sodium (HPS), metal halide (MH), and ceramic metal halide (CMH/LEC) ballasts rated at up to 1000W per ballast, up to four ballasts per controller.

Voltage: The universal plug supports both 120V and 240V circuits. The 30A relay limit applies regardless of voltage — calculate your total ballast amperage at your operating voltage before wiring. At 240V, four 1000W ballasts typically draw well within the 30A limit; at 120V, four 1000W ballasts may approach or exceed 30A depending on ballast efficiency ratings.

Trigger input: The included trigger cable is 120V. This is compatible with standard mechanical outlet timers, digital programmable timers, and most environmental controllers that output a 120V switched signal to trigger external loads. The controller does not accept 0–10V or dry-contact trigger inputs — verify your control device outputs a 120V signal before purchasing.

What this controller does not do: The MASTER 4 does not dim ballasts, does not communicate over digital protocols (0–10V, DALI, or proprietary networks), and does not include built-in power metering. It is a relay switch, not an intelligent ballast driver.

You can also run complementary lighting products through separate circuits. For example, if you are using Faven Chroma power cords for LED supplemental lighting, those run on their own circuit while the MASTER 4 handles the HID ballasts.

Installation requires working with line-voltage wiring. LTL Controls explicitly recommends consulting a certified electrician before installing or using this controller, especially if you are not familiar with electrical wiring and circuits.

Usage Guidelines

The MASTER 4 functions as a relay switch between your timer and your ballasts. The basic operating model is:

1. Your timer or environmental controller outputs a 120V signal on its switched outlet.
2. The 120V trigger cable connects from that switched outlet to the trigger input on the MASTER 4.
3. When the timer switches on, the MASTER 4’s relay closes and supplies power to the connected ballasts.
4. When the timer switches off, the relay opens and all connected ballasts power down simultaneously.

Load calculation: Before connecting ballasts, calculate total amperage draw at your operating voltage. Check the ballast manufacturer’s specifications for actual draw (not nominal wattage). Leave at least 20% headroom below the 30A relay limit as a safety margin. Do not exceed the relay’s rated amperage under any circumstances.

Photoperiod scheduling: The MASTER 4 itself has no scheduling logic — it only follows the trigger signal. Set your photoperiod (typically 18/6 for vegetative growth, 12/12 for flowering) on your timer or environmental controller. The MASTER 4 will switch all four lights on that schedule.

Inrush current: HID ballasts produce a current surge at startup that is higher than their running amperage. This is normal behavior and the relay is designed to handle it, but it is a factor to be aware of when sizing your circuit breakers and wiring upstream of the controller.

How to Install the LTL Controls MASTER 4-Light Relay Controller

Safety notice: LTL Controls recommends consulting a certified electrician before installing or using this controller, especially if you are unfamiliar with electrical wiring and circuits. The steps below describe the general installation sequence; always follow local electrical codes and the manufacturer’s wiring instructions.

1. Verify your circuit: Confirm the circuit breaker serving the MASTER 4’s outlet is rated for the total load. For 240V operation, ensure you have a properly wired 240V outlet compatible with the universal plug.
2. Position the controller: Mount or place the MASTER 4 in a dry, accessible location near the ballasts. Keep it off the floor and away from standing water. Ensure adequate ventilation around the unit.
3. Connect the ballasts: Plug each HID ballast into an outlet on the MASTER 4. Do not exceed four ballasts for the MASTER 4 or the 30A relay rating. Verify the total ballast amperage draw is within the relay’s rated limit before powering on.
4. Connect the trigger cable: Plug the included 120V trigger cable into the MASTER 4’s trigger input. Run the other end to the switched outlet on your timer or environmental controller.
5. Set your timer: Program your timer or controller for the desired photoperiod schedule. Double-check that the timer’s switched outlet is the one connected to the trigger cable — not the timer’s always-on pass-through outlet if one is present.
6. Test before loading plants: With ballasts connected, switch the timer on manually and verify all ballasts power up. Switch the timer off and verify all ballasts power down. Check for any unusual sounds, heat, or smells from the controller or wiring during the first few minutes of operation.
7. Monitor initial operation: Check the controller and all connections after the first few on/off cycles. Ensure outlet connections are secure and no connections are warm to the touch beyond normal operating temperature.

For T5 fluorescent or other lighting in the same space, such as a T5 grow light fixture used for seedlings or clones, run those on a separate circuit and timer independent of the MASTER 4.

Sources & Further Reading