NEC 700.10(D)

[dan3388]

A few questions regarding the protection of feeder-circuit wiring and generator control wiring:

• In a building with fire sprinkler protection, is the interstitial space considered protected under the requirements of 700.10(D), if there sprinklers are not installed above the ceilings?
• Does anyone know of a conduit type that is a UL-listed "electrical circuit protective system" with a minimum 2-hour fire rating?
• Does anyone know of a junction/pull box type that is a UL-listed "electrical circuit protective system" with a minimum 2-hour fire rating?
• In general, any recommendations for the "best" method to meet the requirements of NEC 700.10(D)?

 

[Buck Parrish]

That should be in the UL Guide - code FHIT
Most that we do go from the sprinklered electric room straight down and encased in concrete to the generator

 

[frank everingham]

this article can be hard to interpret for a contractor or inspector.be sure that 700.10( d) applies to your situation. if this has to do with a health care building in article 517,the references in 517 to 700.10d are not clear. the 2020 code tries to clear them up. the sprinkler system has to protect the feeders even above a drop ceiling to meet the requirements of 700.10d(1). conduit is not fire rated. same for the junction boxes. you can go underground, a fire rated shaft,look into m.i. cable, or draka 2 hour fire resistive cable. the a.h.j. has the final say

 

[Don Organ]

Without knowing a lot of details about your interstitial space, I cannot say if it is considered a protected space. But as far as your electrical circuit protective system per NEC-700, you can go with conduit in concrete the length of the run, or there are two other options. One is you can enclose the conduit in a Gypboard built enclosure, with rated access doors at the boxes, Or you can use a two hour rated fire wrap (its a foil faced intumescent insulation) that will give it a two hour rating. We are currently using the Wrap at a major Airport. And last, they make a Mineral insulated (MI) cable that is fire rated for 2 hours, if available for what you need size wise,.
But run those options by your AHJ to see which he will approve. The intumescent wrap is available from a few companies including 3M, We just used The Fire wrap at an Airport generator system. The wrap can be used on J-Boxes with an engineering judgement from 3M or the Manuf. as to how to apply to achieve the rating, and is listed/Labeled material. Hope that gives you something to think about.

 

[steveshow]

If an installation meets the requirements of 700.10(D)(2)(1) (cable/ raceway installed in an area that is fully protected by a fire suppression system) do the requirements of 695.6(A)(2) ((1) The cable or raceway is encased in a minimum 2 inches of concrete. (2) The cable or raceway is a listed fire resistive cable system (3) The cable or raceway is a listed electrical circuit protective system) not apply?

 

[Boingo1972]

Hi all. A newbie here on this forum. I'm an engineer for a wire and cable manufacturer, the largest one, and specialize in fire resistive cable products that meet code. So I have to understand the codes really well regarding this topic. The problem with the NEC in these instances is that most don't really know the codes since they don't use them very often. I actually do, every day in fact, so I have a pretty good understanding of them. I always want to preface my responses with the fact that the local AHJ must approve anything when it comes to fire resistive cable installs. They can have their own interpretation of the codes, but I teach classes on it to most of them across the country. What I'll talk about is actual code compliance and not opinion.

First, lets talk about the NEC. That does not include any local code requirements and only federal requirements (NFPA 70).

In the NEC, Article 700 illustrates 5 ways to be code compliant with fire resistive systems. Of those 5, one is the use of "sprinkler systems". The key here is what other articles reference article 700. 695, which covers fire pumps doesn't....so fire pumps don't have the "sprinkler system" caveat.....so that's not an option and for good reason. If you're using a sprinkler system to provide fire protection.....and your powering the fire pump with wire that will fail during a fire.......well not a good engineering idea since the sprinklers won't work to provide the protection. The NEC feels the same way.

Depending on your states NEC version.....in 2017, you can't use the sprinkler defense on COPS systems or Fire Pumps. In the 2020 NEC, Hospitals are no longer applicable either. Heck MC fire resistive cables are no longer allowed in hospitals in the 2020 NEC as they removed the reference to article 700 altogether.

If you have any questions about your situation, please let me know. There are only a handful of people whom know the codes and what is acceptable regarding fire resistive installations. I'm not trying to sell anything here but want you to know what the code allows. I see it all the time whereas a local AHJ requires things that are not required and believe that because they don't understand the code.

One thing I will leave you with is this: Building codes and the NEC are different animals. Building codes allows for a build up for a fire rating......meaning 1 sheet of drywall is 1 hour and 2 sheet is 2 hours. So if you add them together you get a cumulative amount. Electrical code doesn't work that way. You cannot stack the ratings. A system has a rating and that's all you get. Putting a 1 hour system in a 1 hour room only gets you a 1 hour rating. And for NEC codes.....the install is a system, not a bunch of parts that make that system. Each one is different and parts are NOT interchangeable amongst those systems. It has to be installed with all the parts that make the "system".

Like I said....contact me if you have questions as I teach classes on this to all the AHJ's across the country and lots of consulting engineering firms. I'm not selling anything just want to educate what is required.

Thanks,
Colin

 

[Boingo1972]

And to expand on what Don Organ said....which he is correct. The UL directory on FHIT systems allow for the use of fire resistive cable systems. They are "systems" and not components of them and must be followed to the letter. However there are a lot of systems available. Mat wrapping being one, MI being another, but there are many other cable system types. Some MC cable, some a pipe and wire system in EMT or other conduits. Each system has limitations and required components, but there are many options available. Again, state you need in detail and I can help determine which one is best for you, whether my company makes it or a competitor does. Wrapping conduit per FHIT 7 will cost about $20K per 1000 feet, and that's the only conduit wrap allowed. Other systems can be much less expensive and easier to install (EMT with wires for example FHIT 25C or FHIT 28E, two different manufacturers). Again, there are options....all being expensive regardless, but some options work better than others depending on the installation requirements.

 

[steve66]

this article can be hard to interpret for a contractor or inspector.be sure that 700.10( d) applies to your situation. if this has to do with a health care building in article 517,the references in 517 to 700.10d are not clear. the 2020 code tries to clear them up. the sprinkler system has to protect the feeders even above a drop ceiling to meet the requirements of 700.10d(1). conduit is not fire rated. same for the junction boxes. you can go underground, a fire rated shaft,look into m.i. cable, or draka 2 hour fire resistive cable. the a.h.j. has the final say

517.26 (2) in the 2020 NEC makes it pretty clear for a health care facility :

700.10(D) Shall not apply.

 

[Skimattacks]

Hi all. A newbie here on this forum. I'm an engineer for a wire and cable manufacturer, the largest one, and specialize in fire resistive cable products that meet code. So I have to understand the codes really well regarding this topic. The problem with the NEC in these instances is that most don't really know the codes since they don't use them very often. I actually do, every day in fact, so I have a pretty good understanding of them. I always want to preface my responses with the fact that the local AHJ must approve anything when it comes to fire resistive cable installs. They can have their own interpretation of the codes, but I teach classes on it to most of them across the country. What I'll talk about is actual code compliance and not opinion.

First, lets talk about the NEC. That does not include any local code requirements and only federal requirements (NFPA 70).

In the NEC, Article 700 illustrates 5 ways to be code compliant with fire resistive systems. Of those 5, one is the use of "sprinkler systems". The key here is what other articles reference article 700. 695, which covers fire pumps doesn't....so fire pumps don't have the "sprinkler system" caveat.....so that's not an option and for good reason. If you're using a sprinkler system to provide fire protection.....and your powering the fire pump with wire that will fail during a fire.......well not a good engineering idea since the sprinklers won't work to provide the protection. The NEC feels the same way.

Depending on your states NEC version.....in 2017, you can't use the sprinkler defense on COPS systems or Fire Pumps. In the 2020 NEC, Hospitals are no longer applicable either. Heck MC fire resistive cables are no longer allowed in hospitals in the 2020 NEC as they removed the reference to article 700 altogether.

If you have any questions about your situation, please let me know. There are only a handful of people whom know the codes and what is acceptable regarding fire resistive installations. I'm not trying to sell anything here but want you to know what the code allows. I see it all the time whereas a local AHJ requires things that are not required and believe that because they don't understand the code.

One thing I will leave you with is this: Building codes and the NEC are different animals. Building codes allows for a build up for a fire rating......meaning 1 sheet of drywall is 1 hour and 2 sheet is 2 hours. So if you add them together you get a cumulative amount. Electrical code doesn't work that way. You cannot stack the ratings. A system has a rating and that's all you get. Putting a 1 hour system in a 1 hour room only gets you a 1 hour rating. And for NEC codes.....the install is a system, not a bunch of parts that make that system. Each one is different and parts are NOT interchangeable amongst those systems. It has to be installed with all the parts that make the "system".

Like I said....contact me if you have questions as I teach classes on this to all the AHJ's across the country and lots of consulting engineering firms. I'm not selling anything just want to educate what is required.

Thanks,
Colin

Hi Colin,

Two questions here on the 2hr fire rating of the feeders on an emergency system at a college. An upcoming engineered project we have has us installing a dual purpose docking station on the existing emergency system by tapping into an existing nema3r junction box that has the feeders from the generator running through it. This junction box is installed outside the building right by the generator. From the junction box the wiring is in PVC under the concrete which also is the pad for the generator. We are trying to determine if the wiring between the junction box and docking station has to be 2hr fire rated outside. If so, it seems strange that the existing junction box is not 2hr fire rated. This installation was done around 5-6 years ago. As of right now we are being told to change the junction box to a 2hr fire rated nema4x box and install either MI Cable, Vitalink, or FRE conduit. If we do change this all out, I question if the installation will meet the 2hr fire rating as the docking station only has an aluminum nema3r enclosure. This is in MA and the MA amendments delete 700.10 (D)(1).

Thanks,

Matt

 

[Boingo1972]

Hi Matt!
Generally, any wires or conduits installed outside the envelope of the building do not need to have any fire resistive rating. However there is a caveat to this. Outside is considered 12 inches or more outside the building per all FHIT documents. So if your 12 inches or more past the building penetration point you are considered outside on emergency circuits and no fire rating is necessary. Sometime parking garages are classified as inside the building though. This is most likely the reason for the 3R box since no fire rating is necessary outside. Of course that what code says, and an AHJ may have other ideas and is the person whom will ultimately approve it. Does an aluminum box hold a fire rating? That answer is NO! Boxes don't hold ratings, nor does conduits or cables. The combination of them within it's system does. Each system is different and will use different items that are specific to THAT system and not interchangeable. I can tell you that no 2 hour fire rated system will have any aluminum in it, because aluminum won't survive the 1850 deg F testing temperatures for 2 hours. Aluminum will melt before that, so you won't see any aluminum on a fire resistive cable system.

If your hand is forced to use a 2 hour rated system for some odd reason, be cautious on the products mentioned above. MI has a bare copper sheath on it and will tarnish and turn colors (not to mention kind of difficult to work with). So will MC options like Vitalink of Lifeline, however both those can come with a black jacket over the copper armor. Bad part is that no one has it and it will have to be made, which means waiting and minimum order quantities of ~500 feet or more. If you have to, the best option I think would be either EMT with RHW-2 wires or FRE with RHW-2 wires (both are covered under UL's FHIT 25C). But again, outside is covered by NEC Article 225 and no where in that article will is reference fire resistive ratings, so they shouldn't be required.

 

[Skimattacks]

Hi Matt!
Generally, any wires or conduits installed outside the envelope of the building do not need to have any fire resistive rating. However there is a caveat to this. Outside is considered 12 inches or more outside the building per all FHIT documents. So if your 12 inches or more past the building penetration point you are considered outside on emergency circuits and no fire rating is necessary. Sometime parking garages are classified as inside the building though. This is most likely the reason for the 3R box since no fire rating is necessary outside. Of course that what code says, and an AHJ may have other ideas and is the person whom will ultimately approve it. Does an aluminum box hold a fire rating? That answer is NO! Boxes don't hold ratings, nor does conduits or cables. The combination of them within it's system does. Each system is different and will use different items that are specific to THAT system and not interchangeable. I can tell you that no 2 hour fire rated system will have any aluminum in it, because aluminum won't survive the 1850 deg F testing temperatures for 2 hours. Aluminum will melt before that, so you won't see any aluminum on a fire resistive cable system.

If your hand is forced to use a 2 hour rated system for some odd reason, be cautious on the products mentioned above. MI has a bare copper sheath on it and will tarnish and turn colors (not to mention kind of difficult to work with). So will MC options like Vitalink of Lifeline, however both those can come with a black jacket over the copper armor. Bad part is that no one has it and it will have to be made, which means waiting and minimum order quantities of ~500 feet or more. If you have to, the best option I think would be either EMT with RHW-2 wires or FRE with RHW-2 wires (both are covered under UL's FHIT 25C). But again, outside is covered by NEC Article 225 and no where in that article will is reference fire resistive ratings, so they shouldn't be required.

Hi Colin,

The existing junction box is mounted right on the building wall with the conduits (EMT with XHHW-2 wires) coming through the back of the of box through a mechanical room to a 2hr fire rated electrical room. The conduits run a good 30' in the mechanical room to the outside wall. In the mechanical room it appears that conduits are covered in 2hr fire rated plywood. The existing setup here is not ideal. I am not sure on the thickness of the brick and block wall but it seems we would have needed to have the "2hr fire rated raceway" stick 12" past the outside wall to not require the 2hr fire rating outside the building?

I had looked into the lifeline RHW-2 wire and was curious if we could use EMT outside with steel raintight Raco connectors/couplings. The specs on that wire stated that Raco steel compression connectors/couplings and EMT are an approved horizontal method, but no mention of the raintight connectors/couplings. I assume their connectors/couplings are the same item with just the added gaskets for the raintight rating.

Thanks,

Matt

 

[Boingo1972]

Hi Colin,

The existing junction box is mounted right on the building wall with the conduits (EMT with XHHW-2 wires) coming through the back of the of box through a mechanical room to a 2hr fire rated electrical room. The conduits run a good 30' in the mechanical room to the outside wall. In the mechanical room it appears that conduits are covered in 2hr fire rated plywood. The existing setup here is not ideal. I am not sure on the thickness of the brick and block wall but it seems we would have needed to have the "2hr fire rated raceway" stick 12" past the outside wall to not require the 2hr fire rating outside the building?

I had looked into the lifeline RHW-2 wire and was curious if we could use EMT outside with steel raintight Raco connectors/couplings. The specs on that wire stated that Raco steel compression connectors/couplings and EMT are an approved horizontal method, but no mention of the raintight connectors/couplings. I assume their connectors/couplings are the same item with just the added gaskets for the raintight rating.

Thanks,

Matt

HI Matt,
I know we just spoke on the phone but wanted to reply for the sake of anyone interested.

You are correct about having the existing conduits stick 12" past the outside of the wall to maintain the fire rating. The second question is can you use the raintight compression fittings with the Lifeline RHW-2 in EMT system (FHIT 25C). You situation is a bit different than most so that answer is yes and no. You CAN use the raintight couplers if your outside the building, but you cannot inside the building. The reason is outside, no rating is necessary but inside it is. So when inside you have to follow the FHIT to the letter, but outside you can treat it just like building wire and use any coupler. And honestly outside the building there would be no reason to run a highly engineered and expensive RHW-2 wire.

I think for you, and now understanding that your circuit is probably not for emergency equipment, you're tapping into a circuit outside the building and your runs will be external to the building there is no need to have a fire resistive system installed.

 

[njpowers2]

Hi Matt!
Generally, any wires or conduits installed outside the envelope of the building do not need to have any fire resistive rating. However there is a caveat to this. Outside is considered 12 inches or more outside the building per all FHIT documents. So if your 12 inches or more past the building penetration point you are considered outside on emergency circuits and no fire rating is necessary.

Hey Colin,

I was hoping to gain some clarity on your point above. Do you know the code reference for this item? I only ask because we are doing a design for a school, in which we are installing a new exterior generator. This generator will feed NEC 700 loads. We will be running the NEC 700 feed from the generator into a 2-hour rated interior electrical room but weren't sure whether the exterior feeder needs to be concrete encased and how exactly to handle the conduit that will run up the exterior of the wall and penetrate into the electrical room.

We plan to discuss any solution with the AHJ to ensure they agree but any insight would be appreciated.

 

[Boingo1972]

Hey Colin,

I was hoping to gain some clarity on your point above. Do you know the code reference for this item? I only ask because we are doing a design for a school, in which we are installing a new exterior generator. This generator will feed NEC 700 loads. We will be running the NEC 700 feed from the generator into a 2-hour rated interior electrical room but weren't sure whether the exterior feeder needs to be concrete encased and how exactly to handle the conduit that will run up the exterior of the wall and penetrate into the electrical room.

We plan to discuss any solution with the AHJ to ensure they agree but any insight would be appreciated.

Morning njpowers2! I can help you out here, but to understand it you need to follow the paper trail logic first. First, look at the building code (IBC) definitions, specifically "Fire Area", "Inside" and "Outside". Fire Area will show that a buildings fire area is inside a building with an exception for roof overhangs in certain instances and inside/outside will be pretty clear. Once you establish you are not "inside" a building for your exterior generator feeds you follow the NEC for outside branch circuits and feeders (Article 225). Article 225 does not have any references to fire resistive ratings and therefore it's not necessary. Now once you enter the building other rules apply. NEC 700.10(D) allows for several different ways to achieve a 2 hour fire resistive rating. Of those, one is fire resistive cable systems and another is building assemblies that have a 2 hour rating. There are others but those are the ones you are concerned with. Keeping in mind that only 1 must be met to achieve the rating. I believe you are entering the building into an electrical room which should hold a 2 hour rating on its own. If so, that room is an "assembly" and the room holds the rating so the items inside don't have to. Rooms are listed as thermal barrier systems (XCLF) and described in the UL Guide Information for Electrical Equipment — The White Book. So, if your outside a building and entering the structure into a 2 hour fire rated room......you do not need to use Fire Resistive Cable Systems and can use regular building wire for the entire circuit.

To add more info just in case your AHJ has concerns on it, I'll add a bit more. Article 728 (Fire Resistive Cable Systems) will override all other NEC articles should a conflict occur (728.3). Installations under 728.5 says:
Fire-resistive cable systems installed outside the fire-rated rooms that they serve, such as the electrical room or the fire pump room, shall comply with the requirements of 728.5(A) through (H) and all other installation instructions provided in the listing.

So when inside those rooms, it's not necessary! Then we have the actual controlling document when installing fire resistive cable systems which is a UL document called an FHIT XXX. 728 references the "listing" a lot and the FHIT XXX is that systems listing, in essence an FHIT must be followed per 728 which overrides the rest of the NEC or simply, follow the FHIT to the letter. In the UL published Guide Info for these systems it says:

These systems are intended to be installed in interior environments with representative heating and air conditioning, unless stated otherwise in the individual system.

There is not 1 listed FHIT system that states anything about being outside a building (nor Article 225) which again confirms they are not necessary outside.

So in your case, being outside and entering a fire rated electrical room would negate the need to use fire resistive cable systems and I would recommend you use regular wire and save the money.

Hope this helps!

Colin

 

[njpowers2]

Morning njpowers2! I can help you out here, but to understand it you need to follow the paper trail logic first. First, look at the building code (IBC) definitions, specifically "Fire Area", "Inside" and "Outside". Fire Area will show that a buildings fire area is inside a building with an exception for roof overhangs in certain instances and inside/outside will be pretty clear. Once you establish you are not "inside" a building for your exterior generator feeds you follow the NEC for outside branch circuits and feeders (Article 225). Article 225 does not have any references to fire resistive ratings and therefore it's not necessary. Now once you enter the building other rules apply. NEC 700.10(D) allows for several different ways to achieve a 2 hour fire resistive rating. Of those, one is fire resistive cable systems and another is building assemblies that have a 2 hour rating. There are others but those are the ones you are concerned with. Keeping in mind that only 1 must be met to achieve the rating. I believe you are entering the building into an electrical room which should hold a 2 hour rating on its own. If so, that room is an "assembly" and the room holds the rating so the items inside don't have to. Rooms are listed as thermal barrier systems (XCLF) and described in the UL Guide Information for Electrical Equipment — The White Book. So, if your outside a building and entering the structure into a 2 hour fire rated room......you do not need to use Fire Resistive Cable Systems and can use regular building wire for the entire circuit.

To add more info just in case your AHJ has concerns on it, I'll add a bit more. Article 728 (Fire Resistive Cable Systems) will override all other NEC articles should a conflict occur (728.3). Installations under 728.5 says:
Fire-resistive cable systems installed outside the fire-rated rooms that they serve, such as the electrical room or the fire pump room, shall comply with the requirements of 728.5(A) through (H) and all other installation instructions provided in the listing.

So when inside those rooms, it's not necessary! Then we have the actual controlling document when installing fire resistive cable systems which is a UL document called an FHIT XXX. 728 references the "listing" a lot and the FHIT XXX is that systems listing, in essence an FHIT must be followed per 728 which overrides the rest of the NEC or simply, follow the FHIT to the letter. In the UL published Guide Info for these systems it says:

These systems are intended to be installed in interior environments with representative heating and air conditioning, unless stated otherwise in the individual system.

There is not 1 listed FHIT system that states anything about being outside a building (nor Article 225) which again confirms they are not necessary outside.

So in your case, being outside and entering a fire rated electrical room would negate the need to use fire resistive cable systems and I would recommend you use regular wire and save the money.

Hope this helps!

Colin

Thanks for the fast and thorough response! The way you laid it out makes sense to me and I would be surprised if the AHJ felt differently!