DA Form 7452-8-R: Signal Ground Reference Checklist (LRA)

DA Form 7452-8-R: Signal Ground Reference Checklist (LRA) – Maintaining reliable grounding and bonding systems is critical for Command, Control, Communications, Computers, Intelligence, Surveillance, and Reconnaissance (C4ISR) facilities. DA Form 7452-8-R serves as the official checklist for inspecting the Signal Ground Reference Subsystem in existing U.S. Army facilities.

What Is DA Form 7452-8-R?

DA Form 7452-8-R (FEB 2002) is titled “Signal Ground Reference Subsystem Checklist for Existing Facilities (LRA).” It is prescribed for use with TM 5-690, Grounding and Bonding in Command, Control, Communications, Computer, Intelligence, Surveillance, and Reconnaissance (C4ISR) Facilities (15 February 2002), with the U.S. Army Corps of Engineers (COE) as the proponent agency.

This form helps inspectors, engineers, and facility managers systematically evaluate the condition and performance of the signal reference subsystem in legacy C4ISR buildings. It complements other DA forms in the 7452 series for earth electrodes, fault protection, lightning protection, and shielding.

Download the official PDF here: DA Form 7452-8-R

Purpose of the Signal Ground Reference Subsystem

The signal ground reference subsystem (also called signal reference subsystem) provides a common low-impedance reference for electronic equipment. It minimizes voltage differences between devices, reduces noise on signal paths, prevents ground loops, and supports reliable data transmission while maintaining electromagnetic compatibility (EMC), TEMPEST, and EMP protection.

In C4ISR facilities, it works alongside:

  • Earth electrode subsystem (connection to ground).
  • Fault protection (safety grounding).
  • Lightning protection.
  • Facility shielding.

Proper signal grounding is essential for sensitive electronics to avoid interference, ensure signal integrity, and comply with safety and security standards.

Key Sections of DA Form 7452-8-R

The form guides a thorough visual and electrical inspection. Typical items include:

  1. Facility Identification — Name, date (YYYYMMDD), location, and inspector.
  2. Layout Sketch or Drawing — Sketch the existing signal ground reference subsystem or attach current engineering drawings.
  3. Visual Inspection — Check for deterioration, burning, corrosion, or physical damage. Record deficiencies by location.
  4. Continuity Checks — Verify grounding circuits, connectors, joints, bonds, and fittings for proper installation, tightness, and absence of cracks.
  5. Resistance Measurements — Measure resistance between connectors, joints, bonds, and fittings using a double balanced DC bridge. Record values.
  6. Earth-to-Ground Resistance — Measure overall subsystem resistance to earth using the fall-of-potential method.

All deficiencies must be documented with locations for corrective action.

Why This Checklist Matters for Existing Facilities?

Existing C4ISR facilities often follow varied older codes and may have incomplete or degraded grounding. The form supports:

  • Facility surveys and performance evaluations.
  • Identification of upgrades needed during modifications or equipment changes.
  • Compliance with integrated grounding practices for safety, lightning protection, EMI/EMP hardness, and signal security.

Regular use helps maintain configuration control, supports maintenance records, and ensures the subsystem continues to minimize interference and provide stable references.

  • Follow TM 5-690 for detailed design, inspection, and maintenance procedures (publicly available via WBDG or Army sources).
  • Integrate with other subsystems — signal grounds often interconnect with safety grounds but require careful management to avoid loops.
  • Use proper bonding techniques, conductor sizes, and materials.
  • Document baseline configurations and track changes.
  • For new facilities, refer to the companion DA Form 7452-3-R (Signal Ground Reference Subsystem Checklist for New Facilities).

Pro Tip: Always use calibrated test equipment and qualified personnel trained in C4ISR grounding requirements. Poor grounding can compromise mission-critical systems.

Who Should Use This Form?

  • U.S. Army electrical inspectors and engineers.
  • Facility managers and maintenance teams at C4ISR sites.
  • Contractors performing upgrades or surveys on Army installations.
  • Anyone responsible for grounding compliance in sensitive electronic environments.

Stay Compliant and Mission-Ready

Effective grounding and bonding protect personnel, equipment, and classified information while ensuring operational reliability. DA Form 7452-8-R is a key tool in this process for legacy facilities.

Official Download: https://armypubs.army.mil/pub/eforms/DR_a/pdf/A7452_8_R.pdf

For the full technical manual, search for TM 5-690 on official Army or WBDG platforms.