PH120 vs PH30 vs PH60: What Does Fire Rating Really Mean?

Published by Chatnow Technology · October 2026

If you specify or buy fire-resistant cable, you've seen the codes: PH30, PH60, PH120. They look similar but mean very different things - and choosing the wrong one can fail inspection, compromise safety, or waste budget.

This article explains what these ratings mean, how they are tested, and how to select the right cable for your project.

What Is a PH Rating?

PH stands for "Performance in Fire." The PH classification comes from BS EN 50200, the harmonized European standard for testing the circuit integrity of small cables used in emergency circuits.

The test exposes the cable to a direct flame at approximately 842°C with mechanical shock applied to the mounting board throughout the test. The cable passes if it continues to carry current and no short circuit or break occurs.

The number after "PH" indicates the minimum duration, in minutes, that the cable maintained circuit integrity under these conditions. The full range includes PH15, PH30, PH60, PH90, and PH120.

PH30 vs PH60 vs PH120: The Key Differences

PH30 is the minimum for fire alarm circuits in standard installations. The cable must survive 30 minutes of direct flame with mechanical shock.

PH60 is the minimum for emergency lighting circuits in standard installations. It provides double the survival time of PH30.

PH120 is the enhanced rating. It covers both fire alarm and emergency lighting circuits and provides 120 minutes - two full hours - of circuit integrity. PH120 cables must also pass BS 8434-2, which adds a 930°C flame and water spray test.

Why the Test Conditions Matter

The PH test is not just about how long the cable survives. It also tests:

Direct flame at high temperature. The standard test uses a flame at approximately 842°C. For enhanced cables, BS 8434-2 raises this to 930°C.

Mechanical shock. Throughout the test, the cable is subjected to repeated impacts. This simulates falling debris and structural movement during a fire.

Water spray (enhanced only). BS 8434-2 adds a water spray phase to simulate firefighting conditions. The cable must maintain circuit integrity through fire, mechanical shock, and water exposure.

A cable that passes PH120 has demonstrated the ability to keep working under the most demanding fire conditions for two full hours.

Watch Our PH120 Fire Test

Standard vs Enhanced: What the Codes Require

BS 5839-1 (fire detection and alarm systems) recommends "standard" fire-resistant cables for most applications. Standard cables need PH30 for alarm circuits and PH60 for emergency lighting.

However, for certain applications - particularly large unsprinklered buildings - BS 5839-1 recommends "enhanced" fire-resistant cables (PH120).

BS 5266-1 (emergency lighting) similarly recommends standard cables for general use and enhanced cables for large or complex buildings where circuits must operate for longer periods to assist evacuation.

If your project is a tunnel, metro station, hospital, airport, or high-rise building, PH120 is often specified. These are environments with high occupant density and long evacuation times, where every minute of circuit integrity matters.

PH Ratings vs Other Fire Standards

PH ratings are not the only fire performance classification. Here's how they compare:

BS 6387 uses a different framework. The "C" test covers fire alone at 950°C for 3 hours. The "W" test covers fire plus water. The "Z" test covers fire plus mechanical shock. A "CWZ" cable has passed all three.

PH120 and CWZ are not directly interchangeable. Always specify the standard required by your fire strategy and confirm the exact cable model is certified to that standard.

How to Choose the Right Rating

Three questions to ask before specifying:

1. What does the fire strategy require? Check your project specification and local building codes. If PH120 is specified, PH30 will not pass.

2. What is the evacuation time? Longer evacuation times require longer circuit integrity. PH120 gives you 120 minutes.

3. Is water exposure a risk? If sprinklers or firefighting water are present, specify a cable tested to BS 8434-2 (part of PH120 certification).

Where PH120 Cables Are Used

PH120 cables are specified in environments where failure is not an option:

🔹 Tunnels and metro stations - long evacuation routes, high occupant density

🔹 Hospitals and airports - continuous operation of critical systems during evacuation

🔹 High-rise buildings - extended evacuation times and complex firefighting access

🔹 Large unsprinklered buildings - where BS 5839-1 recommends enhanced fire resistance

For these applications, the extra 60 minutes of PH120 over PH60 can mean the difference between a controlled evacuation and a disaster.

About Chatnow Technology

Chatnow Technology manufactures PH120 fire-resistant cables tested to BS EN 50200 with 120-minute circuit integrity. Our cables are UL and CE certified and suitable for fire alarm, emergency lighting, and life safety systems in tunnels, metro stations, and public infrastructure projects.

For inquiries or quotes, contact us at monica@chatnow-cable.com or visit www.chatnow-cable.com.

Summary

🔹 PH30 - 30 minutes, fire alarm circuits (standard)

🔹 PH60 - 60 minutes, emergency lighting circuits (standard)

🔹 PH120 - 120 minutes, both circuits, enhanced fire resistance

🔹 PH120 cables must also pass BS 8434-2 with 930°C flame and water spray

🔹 Always check your project specification - PH30 will not substitute for PH120

🔹 For tunnels, metro, hospitals, and high-rise buildings, specify PH120

Chatnow Technology · UL/CE certified cable manufacturer · Fire-resistant, control, and communication cables