Office cubicle fire

[USMC1302]

Did the surge protector/power strip have built-in OCP? In other words a relocatable power tap? Since the OP mentioned it was a military base, I'd be surprised if they were allowed to use a plain old power strip....We had to have an inspection sticker for a coffee pot from base safety.

 

[fbhwt]

Did the surge protector/power strip have built-in OCP? In other words a relocatable power tap? Since the OP mentioned it was a military base, I'd be surprised if they were allowed to use a plain old power strip....We had to have an inspection sticker for a coffee pot from base safety.

The surge protector/power strip did have OCP but did not trip from what I'm being told although the 20 amp breaker did trip. I'm guessing that when the insulation on the factory installed cubicle wiring to the factory installed receptacle melted, it shorted causing the 20 amp breaker to trip. The coffee mess has to be approved by the fire inspector as you stated.

 

[al hildenbrand]

The strongest point I can offer in defense of this interpretation comes from 605.8. It talks about connecting the cubicle to the building’s electrical system. That tells me that it is not treating the cubicle as though it were itself part of the building’s electrical system.

And yet, 605.1 and 605.3 tell us the Utilization Equipment and Lighting Accessories "used within office furnishings" are supplied by wiring systems. (Note: "systems" is plural.)

--AND--

There is a base order that reads: "Electric heaters of the portable type are not to be installed in any building before a fire safety inspection has been made by the Fire Inspector. Electric portable heaters to be acceptable shall meet a standard that requires a thermostat for heat control, and a tip over switch for automatic shut-off if accidentally knocked over".

To me, this says the office furnishing is intended, at the time of installation, to supply "electric heaters of the portable type", meaning the initial wiring, both building and office furnishing, should be configured for the electric heater load.

 

[RB1]

Charlie,

90.2(A) says that the code applies to installation of equipment. It does not mention operation of the equipment.

The purpose of the code is the practical safeguarding from hazards arising from the use of electricity. I don't think it ends at installation. I am guessing that the term use as used in this context is "to take or consume". That definitely occurs after installation.

 

[iwire]

So I went looking at ROPs for 2002, 2005, 2008, 2011 and 2014.

What I find is that as far as cord and plug connected cubicles the only load calculation is for the receptacle they are plugged into.

As for hardwired cubicles I find no direct statement either way in the ROPs. From what I infer the CMP feels all other code sections apply.


That said in my opinion branch circuit stops at outlet where the listed equipment gets connected and that is not in conflict with 'all other code sections apply'.

 

[al hildenbrand]

That said in my opinion branch circuit stops at outlet where the listed equipment gets connected and that is not in conflict with 'all other code sections apply'.

Branch Circuit. The circuit conductors from the final overcurrent device protecting the circuit and the outlet(s).

"Outlet(s)" is plural, and I see no distinction that exclude a group of outlets (in the office furnishing system) IN SERIES with an outlet on the end of the Premises Wiring (System).

As a similar situation, consider 400.7(A)(11) and the products that are a listed assembly specific for this application. One product is PowerBridge. 400.7(A)(11) clearly names both receptacles, that are in series with each other, as Receptacle Outlets.

The conductors between two Receptacle Outlets that are in series with each other are "circuit conductors"

 

[iwire]

"Outlet(s)" is plural, and I see no distinction that exclude a group of outlets (in the office furnishing system) IN SERIES with an outlet on the end of the Premises Wiring (System).

That is what it says, what it means is very much up for discussion.

IMO the office cubical is no more of a Premises Wiring (System) than a relocatable power tap is a Premises Wiring (System).

 

[iwire]

iwire,

Article 605 doesn't need to reference other requirements. There is nothing in Article 605 that modifies the requirements of 210.12(B)(2).

210.12(B)(2) applies to the premises wiring system receptacles. Not the receptacles installed in listed equipment

Using your reasoning, a Furniture Power Distribution Unit could be installed in an assisted living facility with a receptacle outlet located within 1 foot of a sink. The argument would be that GFCI protection is not required because this is part of a listed assembly and Article 210 does not apply.

Exactly, you have described my position perfectly. Just because the result is not palatable does not make it incorrect.

Is it your opinion that the receptacle that is inside the fan and light assembly found in countless bathrooms must be GFCI protected?

 

[kwired]

There is a base order that reads: "Electric heaters of the portable type are not to be installed in any building before a fire safety inspection has been made by the Fire Inspector. Electric portable heaters to be acceptable shall meet a standard that requires a thermostat for heat control, and a tip over switch for automatic shut-off if accidentally knocked over". I am waiting on a report from base safety to see what the fire inspector had to say. These heaters are used all over base, we have problems every year with breakers tripping, this is the first fire I have heard of. I have suggested changing the 20 amp breaker to a 15 amp, at least when the breaker trips due to overload(because other things beside the heater were plugged in) an electrician will have to go reset the breaker. Hopefully the electrician will want to know why the breaker tripped and find out if the heater is approved.

Portable heaters usually have a higher "duty cycle" then cooking appliances or even a coffee pot of similar watt rating. Though you probably won't run into a portable air conditioner in your case, they are higher duty cycle as well. I see more melted cord ends or receptacles from those two appliances then any other appliance. You can include all the safety features you want in the heater and have one that is quite safe, but it doesn't change the fact it draws 1000 to 1500 watts and plugs into the same receptacle as any other heater.

 

[stevenje]

I wouldn't say the cord cap is commonly the problem - I think it is more of an issue with receptacle to cord cap contact. You see these problems the most with the cheap grade receptacles, but the higher grade ones eventually do wear out some and are not immune to this problem either. If it does start in the cord cap it can take out a higher grade receptacle as well. Another problem can be contact resistance in the receptacle to supply wiring connections, again cheap grade receptacles seem to have more issues, but installer error can still take out a high grade receptacle as well.

Your right kwired. The bad connection is the source of the heat. I just see the cord cap in these situations as the first to start the melt down process.

 

[RB1]

Iwire,

I don't think a single receptacle contained within an appliance for the purpose of connecting a component of that appliance is required to comply with Article 210. However, a receptacle that is part of a manufactured wiring system intended for the connection of portable appliances by consumers is required to comply.

Does Article 406 apply to those receptacles?

 

[al hildenbrand]

IMO the office cubical is no more of a Premises Wiring (System) than a relocatable power tap is a Premises Wiring (System).

Yes, a relocatable power tap is not a Premises Wiring (System).

However, in order to be an Article 605 Office Furnishing, the wiring in Office Furnishings IS a wiring system. This is a status a relocatable power tap isn't required to have, and doesn't have. By the definition of Outlet, "wiring system" is enough for the receptacle device or the connection to a luminaire's conductors in Office Furnishing to be, in fact, outlets at points on a wiring system. Utilization Equipment there connected is connected through the Outlet to the conductors that are circuit conductors . . . and circuit conductors is all that is necessary for the definition of Branch Circuit to apply.

In this case, the Code is making us see the Branch Circuit as extending over two wiring systems in series, the Premises Wiring (System) and the Office Furnishing Wiring System.

While I hear your opinion is that the Branch Circuit ends at the Outlet on the Premises Wiring (System), I don't think you can find the Code citation(s) to substantiate it. I HAVE given Code citations to substantiate my opinion in this thread.

 

[fbhwt]

Yes, a relocatable power tap is not a Premises Wiring (System).

However, in order to be an Article 605 Office Furnishing, the wiring in Office Furnishings IS a wiring system. This is a status a relocatable power tap isn't required to have, and doesn't have. By the definition of Outlet, "wiring system" is enough for the receptacle device or the connection to a luminaire's conductors in Office Furnishing to be, in fact, outlets at points on a wiring system. Utilization Equipment there connected is connected through the Outlet to the conductors that are circuit conductors . . . and circuit conductors is all that is necessary for the definition of Branch Circuit to apply.

In this case, the Code is making us see the Branch Circuit as extending over two wiring systems in series, the Premises Wiring (System) and the Office Furnishing Wiring System.

While I hear your opinion is that the Branch Circuit ends at the Outlet on the Premises Wiring (System), I don't think you can find the Code citation(s) to substantiate it. I HAVE given Code citations to substantiate my opinion in this thread.

This is along the lines as to what I was thinking that the office equipment is an extension of the branch circuit. Now if the office equipment was cord and plug connected then that would change everything.

 

[kwired]

Why all the beating around the bush? A 1500 watt heater is somewhat a high risk of such problems whether the outlet it is plugged into met code or not. The risk goes down some with higher grade devices, but any weak connection will eventually fail under that kind of a load.

 

[al hildenbrand]

Now if the office equipment was cord and plug connected then that would change everything.

This point of yours is where I ask you to stretch.

Above, I brought up 400.7(A)(11) and the PowerBridge as it is my contention that, because of the Article 100 Definition of Branch Circuit's use of the term "circuit conductors", there is no break of the circuit conductors between the final Overcurrent Protective Device and the "Outlet(s)". I emphasize that the NEC is silent about connecting an outlet in series with an outlet. . .

Also, consider, that the hardwired connection of circuit conductors of the branch circuit on the end of the Premises Wiring (System), to the circuit conductors Office Furnishing wiring system circuit conductors IS an Outlet, by definition, in my opinion. This hardwired connection is similar to the splice of an electric oven factory installed flexible metal conduit whip to the junction box in the wall behind the oven. . . EXCEPT that the oven wiring is not required to be a "wiring system" the way Office Furnishing IS required.

 

[fbhwt]

This point of yours is where I ask you to stretch.

Above, I brought up 400.7(A)(11) and the PowerBridge as it is my contention that, because of the Article 100 Definition of Branch Circuit's use of the term "circuit conductors", there is no break of the circuit conductors between the final Overcurrent Protective Device and the "Outlet(s)". I emphasize that the NEC is silent about connecting an outlet in series with an outlet. . .

Also, consider, that the hardwired connection of circuit conductors of the branch circuit on the end of the Premises Wiring (System), to the circuit conductors Office Furnishing wiring system circuit conductors IS an Outlet, by definition, in my opinion. This hardwired connection is similar to the splice of an electric oven factory installed flexible metal conduit whip to the junction box in the wall behind the oven. . . EXCEPT that the oven wiring is not required to be a "wiring system" the way Office Furnishing IS required.

There has been different views as to what applies and what does not, I value everyone's opinion. The people occupying said cubicle's could care less what they plug into the provided duplex receptacle in this office wiring system, or if it is plugged into a building wiring system with cord and plug or if it is hard wired to the branch circuit, if they do not have enough space they will plug in another surge protector/power strip. I see it all the time, you can't fix stupid. I will eventually pass this on to the person who has excepted the position of AHJ and let him do what ever he deems necessary to prevent this from happening again. Thanks again for your input as well as everyone else's.

 

[mgookin]

Extension cords were expressly prohibited by NFPA1 for the longest time, then about 10-15 years ago they started allowing RPT's with OCPD to be used. So as long as your "extension cord" has a OCPD you're ok.

 

[kwired]

There has been different views as to what applies and what does not, I value everyone's opinion. The people occupying said cubicle's could care less what they plug into the provided duplex receptacle in this office wiring system, or if it is plugged into a building wiring system with cord and plug or if it is hard wired to the branch circuit, if they do not have enough space they will plug in another surge protector/power strip. I see it all the time, you can't fix stupid. I will eventually pass this on to the person who has excepted the position of AHJ and let him do what ever he deems necessary to prevent this from happening again. Thanks again for your input as well as everyone else's.

Get insurance provider to come in and see what gets plugged in and you may be forced to make some changes or else be dropped or have raised premiums.

Many safety and procedural policies I run into in smaller businesses or sudden changes to such policies usually come about because of insurance audits/inspections.