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Cracking the Codes - for Everyone's Protection

Crack the CodeBuilding Codes, Fire Alarm Codes, Electrical Codes – these aren’t meant to be secret codes, but there’s no question that it is difficult for lay people to keep up with all of them as well as their applicability, their changes, and their specific requirements. We need to know how to crack the codes!

Well, DITEK is here and ready to help with at least one aspect of this challenge – we can highlight a range of current codes that involve electrical surge protection, and we can go further if you need help evaluating your facility for adequate and effective Surge Protective Devices (SPDs). In the sections below, we refer to specific code requirements so that you can go directly to the applicable information regarding SPDs. Here is our version of a decoder ring to help get you started:




At the start, we need to reinforce that regulatory codes are all designed to improve safety. Codes can be national in scope, but they can also be implemented and enforced locally. If you have any question about whether a particular code applies to your situation, contact your local enforcement agency or department to get clarification and assistance. In this blog, we are talking about national-level codes and recommendations that are frequently included in, and implemented by, state and local legislation.

Surge Protective Device Types

Surge protection codes and recommendations sometimes refer to specific “types” of SPDs. This reference does not refer to the technology used in the device (such as Gas Discharge Tubes, or Silicon Avalanche Diodes). Rather, it refers to the Underwriters’ Laboratories (UL) definitions contained in UL 1449. “Type 1” SPDs are permanently installed on the line side or the load side of the service entrance, after the step-down transformer has provided the supply voltage. “Type 2” SPDs are permanently installed only on the load side of the service entrance, after a current limiting device. “Type 3” SPDs are installed 30 feet or more conductor length after the service entrance panel, and can be permanently or temporarily installed, such as surge protective power strips, near the point of use. If a type is specified in the applicable requirement, be sure you install the correct type of SPD.

Fire Protection-Related Codes

Fire-related codes have great breadth because they cover not only the fire alarm systems themselves, but also sources of fire ignition. When properly deployed, SPDs play a role in both areas – reducing the chance that a fire alarm system will be damaged by surges, and reducing the chance that surges will start a fire.

In the NFPA 72 National Fire Alarm and Signaling Code, SPDs are required on all signaling system circuits that enter any building ( This protects the fire alarm system from outside wiring and external antennas that can be particularly vulnerable when exposed to lightning and other electrical disturbances.

In the NFPA 70 National Electrical Code, SPDs are required on the fire pump controller (695.14), on the fire alarm circuits (760.32), on emergency system switchboards and panelboards (700.8), on all voltages for Critical Operation Power Systems (708.20), on wind generation systems (694.7(D)), on industrial machinery with safety interlock circuits (670.6), and on Critical Operation Data Systems (645.18). In the new 2020 Edition, a Type 1 or Type 2 SPD is required for new electrical service supplying a dwelling (230.67).

Other SPD Requirements

In addition, the UL provides requirements for Primary and Secondary SPDs to protect Communication Circuits (UL 497, 497A, and 497B) such as telephone and data cables that can also provide a pathway for electrical surges and spikes to enter buildings or travel between electrical equipment, starting fires or interfering with emergency communications. Section 497B addresses Isolated Loop circuits in data communication and fire alarm circuits specifically. 

Because it is important to protect all possible electrical system entry points from power surges, DITEK has a full selection of cost-effective protectors for incoming utility power, network connections, and control circuit wiring.

If you are unsure whether your fire alarm, power, or communication systems are adequately protected, contact DITEK and your local public safety or code enforcement authorities for guidance and assessment. DITEK can protect your systems with tailored surge protection, helping to keep your occupants, visitors, and facility as safe as possible.

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