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Author Topic: Cited by Fire Marshal - Lots of questions.  (Read 5019 times)

Tim McCulloch

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Re: Cited by Fire Marshal - Lots of questions.
« Reply #10 on: March 22, 2019, 10:15:11 AM »

Oh  yes  14 is not good enough for 20 amp.   needs to be 15 amp breaker.

This is one of the differences in allowed OCPD sizing in residential versus all other "occupancies."  In your home you can have 15 amp outlets and use #14 cords on a 20 amp OCPD, but not anywhere else I'm aware of.
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Stephen Swaffer

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Re: Cited by Fire Marshal - Lots of questions.
« Reply #11 on: March 22, 2019, 01:13:58 PM »

Strictly per the NEC, 15 amp receptacles are allowed on any 20 amp branch circuit in any occupancy.

Extension cords have to be protected per table 402.5, which shows an ampacity of 17 amps for #14 and 23 amps for #12.  OCPD can be rounded up to the next standard size (as lised in code) if you are under 800 amps.  So, 17 rounds up to 20, 23 would round up to 25..

240.5(3) Extension cord sets  Flexible cord use in extension cordsets  shall be considered to be protected  when applied within the extension cord listing requirements

Field assembled extension cord sets used with separately listed and installed components can be supplied with a 20 amp branch circuit provided the wire is 16 AWG or larger 240.5(4)

I didn't know field assembled cords were addressed in the NEC..

Of course, local AHJ and OSHA might have extra regulations.
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Steve Swaffer

Jonathan Johnson

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Re: Cited by Fire Marshal - Lots of questions.
« Reply #12 on: March 22, 2019, 01:43:37 PM »

In your home you can have 15 amp outlets and use #14 cords on a 20 amp OCPD, but not anywhere else I'm aware of.

As I understand it (and I am not an expert), the principle is that the current is limited by the plug design. That is, no device or appliance (in good working condition) with a 15A plug should draw more than 15 amps. So you can "get away with" a 15A receptacle on a 20A circuit. And, since the receptacles on a 15A or 20A circuit are considered "convenience receptacles" rather than dedicated to a particular appliance, multiple 15A receptacles are allowed on a 20A circuit. Nobody is willing to pay for a dedicated circuit to each and every "convenience receptacle" in their home or place of business. It is notable that if a single receptacle is on a dedicated 20A circuit, it MUST be a 20A receptacle (the design of which allows 20A or 15A plugs), not a 15A receptacle. (And, for what it's worth, 15A duplex receptacles are supposed to internally support 20A pass-thru, so the sum of the two receptacles on the duplex face could exceed 15 amps up to the circuit capacity of 20 amps safely.)

Of course, a 3-way splitter without an integrated OCPD blows that theory out of the water. Now you've got three receptacles that could each be loaded with up to 15 amps (for a total up to 20 amps, limited by the circuit OCPD), supplied by a cord and plug rated for no more than 15 amps.
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Tim Weaver

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Re: Cited by Fire Marshal - Lots of questions.
« Reply #13 on: March 23, 2019, 12:13:22 PM »

I don't have any useful advice regarding code, but I did find these and use them at my Church. They have 5 outlets, are steel, and have NO SWITCH which I really like on stage.

https://www.amazon.com/gp/product/B000FVQO0E/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1

Good luck OP.....
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Dan Mortensen

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Re: Cited by Fire Marshal - Lots of questions.
« Reply #14 on: March 24, 2019, 04:35:16 PM »

As I understand it (and I am not an expert), the principle is that the current is limited by the plug design. That is, no device or appliance (in good working condition) with a 15A plug should draw more than 15 amps. So you can "get away with" a 15A receptacle on a 20A circuit. And, since the receptacles on a 15A or 20A circuit are considered "convenience receptacles" rather than dedicated to a particular appliance, multiple 15A receptacles are allowed on a 20A circuit. Nobody is willing to pay for a dedicated circuit to each and every "convenience receptacle" in their home or place of business. It is notable that if a single receptacle is on a dedicated 20A circuit, it MUST be a 20A receptacle (the design of which allows 20A or 15A plugs), not a 15A receptacle. (And, for what it's worth, 15A duplex receptacles are supposed to internally support 20A pass-thru, so the sum of the two receptacles on the duplex face could exceed 15 amps up to the circuit capacity of 20 amps safely.)

Of course, a 3-way splitter without an integrated OCPD blows that theory out of the water. Now you've got three receptacles that could each be loaded with up to 15 amps (for a total up to 20 amps, limited by the circuit OCPD), supplied by a cord and plug rated for no more than 15 amps.

I thought the current was limited by the breaker on the supply outlet?

No matter how many outlets there are on one source, the total current can't exceed the capacity of that breaker or it will pop, which is what is supposed to happen.

On a stage, I don't want separate overcurrent protection devices scattered all over, so that I have to chase down the one that has opened up. I want them all in one place, and whether that's the supply panel in a closet or my portable distro or whatever, I'm only going to one place to fix things.

Or maybe I'm wrong.

I don't get it.
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Stephen Swaffer

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Re: Cited by Fire Marshal - Lots of questions.
« Reply #15 on: March 25, 2019, 12:45:30 PM »


On a stage, I don't want separate overcurrent protection devices scattered all over, so that I have to chase down the one that has opened up. I want them all in one place, and whether that's the supply panel in a closet or my portable distro or whatever, I'm only going to one place to fix things.


Resetting a breaker is not a fix.  Breakers trip because something is overloaded-fixing it requires reducing the load.  Removing a load to make a true fix still requires you to go onstage.

Jonathan's point was that a properly designed load with a 15 amp plug will only draw 15 amps or less.  Plug 2 of these devices into a 20 amp circuit and you can still overload it-which is why in an install your wire has to be sized to the breaker that is protecting it (or vice versa).

Portable cords are a different story.  They are qualified as being acceptable as long as they are used as intended by their UL listing-which will list a specific load.  Unfortunately, too many people think it is OK to keep plugging things as long a breaker does not trip.  That might be OK for the homeowner-but not for the professional.  The professional should know what his load is-if the load is correct and the breaker still trips (a possibility) then there is something else wrong(most likely a loose wire on the breaker).

Code-and often AHJs- take a different view of things depending on the use.  Use an protected triple tap on a construction site?  Might be ok-after all a guy may only be using one tool at a time.  And if a cord gets hot, most likely someone will notice and if a fire starts you have only a few people to evacuate.  On a stage?  Who is paying attention to the cords?  What happens if a fire starts in a packed venue?  Construction sites are generally restricted access-by definition most of the time professional sound gigs invite the public in.  There is an elevated level of responsibility in those cases.
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Steve Swaffer

Brian Jojade

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Re: Cited by Fire Marshal - Lots of questions.
« Reply #16 on: March 25, 2019, 03:47:56 PM »

I don't have any useful advice regarding code, but I did find these and use them at my Church. They have 5 outlets, are steel, and have NO SWITCH which I really like on stage.

https://www.amazon.com/gp/product/B000FVQO0E/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1

Good luck OP.....
Those are great little power strips.  I have several of them that are 30+ years old!  The problem is, that little tab plate makes them potentially not code. There's a silly rule in the code books that says you need to be able to remove a temporary multi-strip outlet without any tools.  So, instead of having screw holes where you can conveniently screw a temporary power strip into place, you end up with the goofy holes in the back tabs that never seem to line up right.  Ugh.

And yes, for entertainment use, any power strip should not have a switch on it.  And for any other use, a power strip should not have a switch on it either!
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Brian Jojade

Dan Mortensen

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Re: Cited by Fire Marshal - Lots of questions.
« Reply #17 on: March 25, 2019, 04:40:19 PM »

Resetting a breaker is not a fix.  Breakers trip because something is overloaded-fixing it requires reducing the load.  Removing a load to make a true fix still requires you to go onstage.

Jonathan's point was that a properly designed load with a 15 amp plug will only draw 15 amps or less.  Plug 2 of these devices into a 20 amp circuit and you can still overload it-which is why in an install your wire has to be sized to the breaker that is protecting it (or vice versa).

Portable cords are a different story.  They are qualified as being acceptable as long as they are used as intended by their UL listing-which will list a specific load.  Unfortunately, too many people think it is OK to keep plugging things as long a breaker does not trip.  That might be OK for the homeowner-but not for the professional.  The professional should know what his load is-if the load is correct and the breaker still trips (a possibility) then there is something else wrong(most likely a loose wire on the breaker).

Code-and often AHJs- take a different view of things depending on the use.  Use an protected triple tap on a construction site?  Might be ok-after all a guy may only be using one tool at a time.  And if a cord gets hot, most likely someone will notice and if a fire starts you have only a few people to evacuate.  On a stage?  Who is paying attention to the cords?  What happens if a fire starts in a packed venue?  Construction sites are generally restricted access-by definition most of the time professional sound gigs invite the public in.  There is an elevated level of responsibility in those cases.

I agree with much of what you say. When I'm doing a show I'm watching the load needs of EVERYTHING that's plugged into my electrical distribution, since as the sound company I'm providing outlets around the stage. If there were a possibility that someone was plugging two 15 amp draws into one of my duplexes, I would talk to them about it before it was powered up.

Sidetracking, since we are doing audio, the actual load and the demanded capacity are often two very different things.

For a while we were doing a series where the power available to us from the venue changed from 100amp 3 phase to something more like 40amp 3 phase for the first hour or two of the soundcheck. We had ammeters separately monitoring both the overall supply and the band power. One band had a stack of Macrotech 7000's or whatever the big one was, like a dozen of them. Their load, at full tilt in that situation, was something like 16amps, 7 amps, and 5 amps per leg. They wanted 100 amp 3 phase for them only.

Back to the OP's situation, we are more often going to have situations where we need 20 outlets onstage for a total draw of about 3 amps or less* than we will have 3 outlets drawing 20 amps or more each. At least in my experience and ignoring lighting/heating.

*I fail to see how each of those outlets or each pair needs its own overcurrent protection.
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Re: Cited by Fire Marshal - Lots of questions.
« Reply #17 on: March 25, 2019, 04:40:19 PM »


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