Surging Phone Lines for Fire Alarm Panels

[SteveH]

Surging Phone Lines for Fire Alarm Panels

For the POTS lines for Fire Alarm Systems, what NEC code section specifically says the phone lines must be surged prior to entering the fire panel dialer? Or, is this not a code requirement? I am not talking about any type of protection the public utilities puts on their lines at the point of entry into a building. I'm talking about the phone lines from the utilities point of demarcation to the fire panel itself. Is a surge required on the phone lines at fire panels? The NFPA-72 National Fire Alarm Code refers you right to the NEC as follows.

The National Fire Alarm Code, Reference: NFPA 72, 2002 Edition, Chapter 4, Paragraph 4.4.4.3) states:

4.4.4.3 Transient Protection. To reduce the possibility of damage by induced transients, circuits and equipment shall be properly protected in accordance with the requirements of NFPA 70, National Electrical Code, Article 800.

Thank You.

 

[smo]

There are a good number of items in the code that are intended for equipment manufacturers, and in my experience this is one of them. Most of the panels I use (Silent Knight, mostly) have the surge protection built into the dialer.

My personal interpretation of the code is that the manufacturers should put this into the panel, but if your panels don't have any surge protection, you should add it. (And upgrade to a better manufacturer that builds that stuff in)

 

[hbiss]

For the POTS lines for Fire Alarm Systems, what NEC code section specifically says the phone lines must be surged prior to entering the fire panel dialer? Or, is this not a code requirement?

The only NEC requirement is a primary protector where the telephone line enters the building. That is always supplied by the telco as part of the NID or separately. What you are talking about is a secondary protector. Primary protectors clamp at 400 volts and are primarily intended to protect premises wiring from lightning and power crosses. If you want to protect your equipment you would want something the clamps well below 400 volts and that's what secondary protectors are for.

Secondary protectors are available in a range of clamping voltages and for a POTS line you have to consider the 90 volt ring voltage. You don't want your protector to trigger on the ring voltage when the line rings so normally you want something with a 150-250 volt clamp voltage.

That said, we normally provide seccondary protection for telephone systems. I have never seen a security panel installed with one. It is true that any reputable manufacturer will provide built in protection in the telephone line input as well as all the other inputs and outputs that have external wiring connected to them. I don't think I would worry about secondary protection on the telephone line unless the system was installed in a lightning prone location. What is important is proper grounding of the panel to a suitable ground.

-Hal

 

[SteveH]

Thank you for your replies. There are certificated fire alarm systems in our area and a UL Auditor came to do an annual audit and said the property needed surge protection on the phone lines. All they did was reference the National Fire Alarm Code, Reference: NFPA 72, 2002 Edition, Chapter 4, Paragraph 4.4.4.3. As stated in my original post, that article simply refers you right to Article 800 of the National Electical Code.

I too could only find the reference to the primary surge suppressor installed by the local utility. Any references to the secondary surges use the statement "if secondary surges are installed".

Steve

 

[tom baker]

Thank you for your replies. a UL Auditor came to do an annual audit

Steve

A UL auditor? Was he/she acutually from UL? Not questioning you but only to find out more about the audit.

 

[SteveH]

A UL auditor? Was he/she acutually from UL? Not questioning you but only to find out more about the audit.

Hi Tom,

Our location has been certified by UL as a Listed 'Service Center'. We applied for and received this certification (a few years ago) to allow us to compete in the Fire Alarm market for systems requiring 'Central Station Service' as listed in Chapter 8.2, NFPA-72 2002ed. Many of our local municipalities have adopted local ordinances that require new Fire Alarm systems to Certificated.

It was during our annual audit and review of one of our actual customer sites that this came up. I just conceded and added the secondary surge on the phone lines on that property because to fight it would not have been worth it.

We do have routine audits so I know this will come up again so I want to be prepared. As we all know, one inspector does not speak for a whole jurisdiction or entity. However, I was just looking for clarification prior to going back and installing the secondary surges on all new and existing sites.

Thanks again.

Steve