What Is Control Wiring?

In a utility or electrical system, control wiring is the low-voltage wiring that is used to send signals, which control how the equipment operates.

Control wiring connects devices that monitor, decide, and act. It carries signals between things like:

• Switches and relays
• Sensors (temperature, pressure, voltage, current)
• Controllers (like PLCs or protection relays)
• Actuators (breakers, contactors, valves)

Control wiring does not carry the main power that runs the equipment. It is different from power wiring, which delivers electricity to do the work (e.g., run motors, lights, transformers). Control wiring is what tells the system when, how, and under what conditions to operate.

Typical Characteristics of Control Wiring

• Usually low voltage (commonly 24V, 48V, 125V DC, or 120V AC in substations)
• Often powered by battery systems for reliability during outages
• Uses smaller conductors than power wiring
• Requires high reliability and clear labeling

Utility System Examples

In a utility (power grid or substation), control wiring is used for:

1. Operating circuit breakers
   • A control signal tells a breaker to open or close.
   • Example: A protection relay detects a fault and sends a signal through control wiring to trip a breaker.
2. Protection systems
   Devices that monitor the system (like overcurrent or distance relays) use control wiring to:
   • Send trip signals
   • Coordinate with other equipment
3. SCADA and remote control
   • Utilities use systems like SCADA to monitor and control equipment remotely
   • Control wiring links field devices to RTUs (remote terminal units)
4. Alarms and status signals
   Control wiring sends signals like:
   • Breaker open/closed status
   • Fault alarms
   • Equipment health

Why Control Wiring Matters

Without control wiring, the system would have no intelligence or coordination—it would just be energized equipment with no safe or automated way to operate.

For example, when a fault occurs on a power line:
1. A relay detects the issue.
2. It sends a signal through control wiring.
3. The circuit breaker trips open.
4. Power flow stops to prevent damage.

So, the control wiring provides the communication necessary for the system’s safety features to work.

Technical Expertise

Our control wiring division has the specialized knowledge and hands-on electrical experience to skillfully complete this delicate, technical work. We have a deep understanding of power system operations, and we work meticulously to ensure that all connections meet the strictest standards.

Safety First

One of our highest priorities as we work is safety—for both the people and the equipment involved. Since our technicians and electricians work around energized systems and critical infrastructure, safety is essential to protect the personnel and the reliability of the power grid. For us, safety is more than just compliance to standard procedures—it’s a commitment to protect lives and maintain dependable power delivery.

Excellent Workmanship

Equally as important as safety is the quality of our work. We strive for perfection in our wiring workmanship. Since we are committed to maintaining the highest standards, our work stands out above all others.

So, if you want to safely complete your upgrade, then leverage the decades of experience we have from many energized substations. We install substation components and wiring to effectively control and communicate with your system. We source the materials and are sure to meet the project specifications.

Specialties

• Panel Fabrication
• Substation Protection & Control
• Relay Upgrades
• RTU Upgrades
• Metering Upgrades
• Battery Installation & Maintenance
• Security Systems
• Transformer Replacements