LTL Controls MASTER Lighting Relay Controllers w/o Timer (120V & 240V Universal Plug) – 8 Light

The LTL Controls MASTER 8 is a dedicated lighting relay controller that allows a single 120V timer or environmental controller to switch up to eight 1000W HID ballasts running on either 120V or 240V power. With a 50-amp relay and a universal plug configuration, it is built for large indoor grow rooms where running multiple ballasts from a single control point reduces wiring complexity and the risk of overloaded circuits.

LTL Controls MASTER 8 Specifications

The MASTER 8 controller is rated for commercial-scale HID lighting setups. The table below covers the key electrical specifications derived from the product description and listed attributes.

Specification	Value
Brand	LTL Controls
Model	MASTER 8 (without timer)
Maximum Ballasts Controlled	8 × 1000W
Load Voltage	120V and 240V (universal plug)
Maximum Relay Amperage	50 A
Trigger Input	120V trigger cable (included)
Timer	Not included — connect external 120V timer
Weight	10 lb (approx.)

Why Choose the LTL Controls MASTER 8

Relay controllers exist because ballasts draw far more current on startup than during steady-state operation. Plugging eight 1000W ballasts directly into a wall timer places excessive inrush current across the timer’s internal contacts, shortening their lifespan or causing immediate failure. The MASTER 8 isolates the timer from the high-current load by using a dedicated relay rated at 50 amps to handle the actual switching. The timer only handles the low-power trigger signal.

LTL Controls positions the MASTER 8 specifically for growers who want to expand beyond what a standard 4-light controller can handle. Below are the practical reasons to consider this controller:

• 50-amp relay for eight 1000W ballasts: The relay is rated to handle up to eight 1000W HID ballasts simultaneously, including the inrush current spikes that occur at switch-on. This rating exceeds what most household-grade environmental controllers can manage internally.
• Dual-voltage load circuit (120V and 240V): The universal plug design means the controller can be wired to either 120V or 240V ballast circuits without purchasing a separate model. Growers running 240V ballasts for efficiency gain access to the same relay protection.
• 120V trigger input keeps existing timers in service: The included 120V trigger cable connects to any standard 120V wall timer or environmental controller. If you already own a timer, you do not need to replace it — the MASTER 8 simply sits between the timer and the ballasts.
• No internal timer to fail or misconfigure: The “without timer” design removes one potential point of failure. Timing is handled by your chosen 120V device, which can be swapped or upgraded independently of the relay controller.
• Scales alongside the MASTER 4: For facilities running both 4-light and 8-light zones, the MASTER 4 and MASTER 8 share the same trigger-cable standard (120V), so the same timer output can drive multiple relay controllers in parallel if needed.

Best Uses for the LTL Controls MASTER 8

This controller is purpose-built for environments where multiple high-wattage HID ballasts need to be switched from a single control point. The following scenarios represent the most common deployments:

• Large grow rooms with eight 1000W HID fixtures: A room running eight DE or single-ended 1000W sodium or metal halide fixtures is the primary use case. The MASTER 8 allows all eight ballasts to be started and stopped together through one 120V trigger, synchronized to a timer or environmental controller.
• Commercial greenhouse supplemental lighting: Greenhouse operators using HID supplemental lighting in multiple bays can use the MASTER 8 to control a full bay of eight fixtures from one timer zone, reducing the number of timers needed across the facility.
• Rooms paired with an environmental controller: When an advanced lighting controller is already managing temperature, CO2, or irrigation, the MASTER 8 accepts that controller’s 120V trigger output and handles ballast switching without adding load to the controller’s internal relay.
• 240V ballast installations: Growers who have wired their rooms for 240V HID ballasts (common in larger commercial builds for reduced amperage draw per circuit) benefit from the universal plug, which accommodates the 240V load side while keeping the control side on standard 120V.
• Multi-zone rooms with staggered lighting cycles: In rooms with multiple independent lighting zones, one MASTER 8 can control each zone’s eight-fixture bank, with each controller receiving its own 120V trigger signal from a separate timer or controller channel.

Compatibility

The MASTER 8 is designed to work with standard HID ballast setups and common environmental control hardware. The following compatibility notes are derived from the product description:

Ballast types: The controller is rated for HID ballasts (high-intensity discharge) at up to 1000W per socket. The description specifies magnetic and electronic 1000W ballasts are the intended load. Do not exceed eight 1000W units (8000W total theoretical load) or the 50A relay maximum.

Load voltage — 120V and 240V: The universal plug allows the load side of the controller to connect to either 120V or 240V circuits. Consult a certified electrician to confirm which voltage your facility’s wiring supports before installation.

Trigger source — any 120V switching output: The 120V trigger cable included with the controller can connect to:

• Standard 120V mechanical or digital wall timers
• Environmental controllers with a 120V lighting trigger output
• Any 120V outlet that is itself controlled by a timer or relay

What is NOT included or compatible: The MASTER 8 does not include an internal timer. It does not provide dimming or variable power output — it is a relay switch only (on/off). It is not designed for LED drivers that require 0–10V dimming signals.

If you are also managing airflow in the same environment, a heavy-duty pedestal fan can be controlled separately through its own timer circuit alongside this controller.

Usage Guidelines

The MASTER 8 is a relay controller, not a timer. Its function is to accept a 120V trigger signal and use that signal to close the relay contacts that supply power to connected ballasts. Correct usage depends on understanding this separation between the trigger circuit and the load circuit.

Trigger circuit (low power): The 120V trigger cable plugs into your timer or environmental controller’s switched outlet. When that outlet turns on, it sends 120V to the controller’s trigger input, which closes the relay and powers the ballasts. When the trigger outlet turns off, the relay opens and all ballasts shut down.

Load circuit (high power): The ballasts plug into the MASTER 8’s output outlets. The load circuit is connected to your room’s 120V or 240V circuit through the universal plug. The total load across all eight outlets must not exceed the 50A relay rating.

Ballast load calculation: Eight 1000W ballasts at 240V draw approximately 4.2A each at steady state, for roughly 33A total on a 240V circuit — well within the 50A relay rating. At 120V, each 1000W ballast draws approximately 8.3A, for roughly 66A total, which would exceed the relay rating. At 120V, limit the load to no more than six 1000W ballasts, or use lower-wattage ballasts to stay within the 50A limit. Consult a licensed electrician for your specific wiring configuration.

Inrush current: HID ballasts draw significantly higher current for the first few seconds of operation than during steady-state running. The 50A relay is rated to handle this inrush load for up to eight 1000W ballasts at 240V. Exceeding this number or running all ballasts on 120V circuits may stress the relay contacts over time.

How to Install the LTL Controls MASTER 8

Installation involves connecting the load circuit to your room’s power supply and the trigger circuit to your timer or controller. The product description recommends consulting a certified electrician before installation if you are unfamiliar with electrical wiring and circuits. The following steps outline the general installation process for a standard HID grow room setup:

1. Plan your electrical layout before starting. Confirm that the circuit(s) you intend to use can support the total amperage of the ballasts you plan to connect. At 240V, eight 1000W ballasts draw roughly 33A at steady state; allow headroom above this figure per standard electrical practice. At 120V, limit total ballast load to stay within the 50A relay rating.
2. Position the controller. Mount or place the MASTER 8 in a location that keeps the controller body away from direct water contact and heat sources. Ensure adequate clearance around the unit for ventilation and cable routing.
3. Connect the load circuit. Plug the controller’s universal load plug into your room’s 120V or 240V circuit. If this is a hardwired installation, have a licensed electrician make the connection. Do not proceed until the load supply is confirmed off at the breaker.
4. Connect the ballasts to the controller’s output outlets. Plug each HID ballast into one of the MASTER 8’s switched output outlets. Do not exceed eight outlets or the 50A relay limit based on your voltage and ballast wattage combination.
5. Connect the 120V trigger cable. Plug the included 120V trigger cable into the trigger input on the MASTER 8 and the other end into the switched outlet on your timer or environmental controller. This is the low-power signal line — it does not carry ballast load current.
6. Set your timer or controller schedule. Program your 120V timer or controller to the desired lighting schedule (for example, 18 hours on / 6 hours off for vegetative growth, or 12/12 for flowering).
7. Test the system. With the load breaker on, trigger the controller manually (or wait for the timer to switch on) and confirm all connected ballasts strike and come to full output. Verify that the ballasts shut off when the trigger signal is removed.
8. Monitor for the first several cycles. Check for any signs of overheating at the plug, outlet connections, or controller enclosure during the first several on/off cycles. Address any warm connections immediately with an electrician before leaving the system unattended.

Sources & Further Reading