Okay, let's break down the situation. You have a conduit run for your fire alarm system that, at one point, has two sections running parallel and closer than 4 feet. One section is in one room, and the other section is in an adjacent room, separated by a cinder block wall.

Is this a violation? The short answer is likely NO, but it depends on the specific code requirements you are under.

Here's the reasoning: 4-Foot Rule Origin

The 4-foot spacing rule primarily comes from Article 760 of the National Electrical Code (NEC) and specifically relates to the separation of fire alarm circuits from non-power-limited circuits. The intent is to prevent interference and accidental contact between these different systems.

Wall as a Barrier

The cinder block wall acts as a physical barrier. If the conduit is securely attached to the wall (properly supported and not just loosely running along it), the wall provides physical separation and reduces the risk of the fire alarm conduit being affected by, or interfering with, other systems on the other side of the wall.

Type of Circuit

This is a crucial point. The 4ft rule mainly applies to non-power-limited fire alarm(NPLF) circuits and their proximity to general power circuits. If you're using power-limited fire alarm (PLFA) circuits or Class 3 circuits, the separation requirements are typically less stringent.

Here's what you need to do to be sure


Identify the governing code



NEC (National Electrical Code)

In the US, most jurisdictions follow the NEC. Find out the specific edition of the NEC that's enforced in your area (e.g., NEC 2023, NEC 2020, etc.).

Local Amendments

Check for any local amendments to the NEC. Cities and counties often modify the NEC to suit their specific needs. Contact your local building department or fire marshal's office.

International Building Code (IBC)

While the IBC doesn't directly specify electrical requirements, it often refers to the NEC.

NFPA 72

This is the National Fire Alarm and Signaling Code. While it does not directly address conduit spacing, it has requirements for circuit integrity, which can indirectly affect how you run your conduit.2.

Check Relevant NEC Sections



Article 760 (Fire Alarm Systems)

Specifically, review Section 760.55 (Separation from Other Circuits). Pay close attention to the subsections that address separation requirements for non-power-limited fire alarm circuits (NPLF) vs. power-limited fire alarm circuits (PLFA)

Article 300 (Wiring Methods)

This article covers general requirements for wiring methods, including raceways (conduit). Look for sections on physical protection and support of raceways.3.

Consider the Conduit System



Conduit Type

Are you using rigid metal conduit (RMC), electrical metallic tubing (EMT), or another type? The type of conduit might influence the interpretation of the code.

Secure Attachment

Make sure the conduit is securely and properly supported to the wall, per code requirements.4.

Consult with the Authority Having Jurisdiction (AHJ)

This is the most important step. The AHJ (usually a building inspector or fire marshal) has the final say on whether your installation is compliant. Explain your situation to them and get their opinion. It's better to address any concerns proactively than to face a violation after the inspection.

In summary:

While the 4-foot separation rule is important, the presence of the cinder block wall significantly changes the situation. The wall provides physical separation and reduces the risk of interference. Review code requirements and speak with your local AHJ to ensure your installation meets local codes and practices. Flag for review