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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => AC Power and Grounding => Topic started by: Jonathan Johnson on May 27, 2014, 02:24:08 AM
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It's an age-old argument that has been going on since the NEMA 5-20R grounding receptacle came into being: do you orient the receptacle with the ground pin up or the ground pin down?
There are valid reasons for both methods:
- Ground pin should be UP because if something falls between the plug and the receptacle, it is less likely to hit the hot pin
- Ground pin should be DOWN because some right-angle plugs are optimized for this orientation
- Ground pin should be UP because some right-angle plugs are optimized for this orientation
- Ground pin should be DOWN because the printing on the yoke of the receptacle indicates this orientation
- Ground pin should be UP because it provides better support for most plugs (excepting #2 above)
- Ground pin should be DOWN because the wife thinks it should look like a little face
I find that reason #6 is the most commonly cited.
Anyway, the purpose of my post is to relate that at my church's annual campout this weekend, the fairgrounds where we were staying had an outdoor stage (which we did not use). On the stage back wall were two "range plug" receptacles (NEMA 10-50R).
Now I've found that most range plugs are built so that the cord exits at a right angle to the pins on the side OPPOSITE the ground pin. This means that for the cord to hang down, the pin should be UP. Being an outdoor stage, the receptacles were equipped with weather-resistant covers, hinged at the top. Now on this stage, the receptacles were installed with the ground pin down (in the "wife says it must make a face" orientation). This means that the cord would go upward, and run into the cover. Since an 8 AWG 3-wire cord is not particularly flexible, you'd never be able to plug in because the cover would be in the way. Sure enough, someone had flipped the cover on one of the receptacles, so it hinged down. That solved the immediate problem but introduced others: the cover is only weathertight with the hinge at the top, and now with the cord extending upward, there is undue strain on the cord, plug, and receptacle.
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It's an age-old argument that has been going on since the NEMA 5-20R grounding receptacle came into being: do you orient the receptacle with the ground pin up or the ground pin down?
There are valid reasons for both methods:
- Ground pin should be UP because if something falls between the plug and the receptacle, it is less likely to hit the hot pin
- Ground pin should be DOWN because some right-angle plugs are optimized for this orientation
- Ground pin should be UP because some right-angle plugs are optimized for this orientation
- Ground pin should be DOWN because the printing on the yoke of the receptacle indicates this orientation
- Ground pin should be UP because it provides better support for most plugs (excepting #2 above)
- Ground pin should be DOWN because the wife thinks it should look like a little face
I find that reason #6 is the most commonly cited.
Anyway, the purpose of my post is to relate that at my church's annual campout this weekend, the fairgrounds where we were staying had an outdoor stage (which we did not use). On the stage back wall were two "range plug" receptacles (NEMA 10-50R).
Now I've found that most range plugs are built so that the cord exits at a right angle to the pins on the side OPPOSITE the ground pin. This means that for the cord to hang down, the pin should be UP. Being an outdoor stage, the receptacles were equipped with weather-resistant covers, hinged at the top. Now on this stage, the receptacles were installed with the ground pin down (in the "wife says it must make a face" orientation). This means that the cord would go upward, and run into the cover. Since an 8 AWG 3-wire cord is not particularly flexible, you'd never be able to plug in because the cover would be in the way. Sure enough, someone had flipped the cover on one of the receptacles, so it hinged down. That solved the immediate problem but introduced others: the cover is only weathertight with the hinge at the top, and now with the cord extending upward, there is undue strain on the cord, plug, and receptacle.
Not to mention that the NEMA 10 series is only a three wire system and requires an external ground wire - which presumably isn't generally used, based on other factors at the site.
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(http://electrical-contractor.net/BCodes/condulet_recpt_1.JPG)
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This means that the cord would go upward, and run into the cover.
Most current electrical codes now call for the ground plug to be up...at least in commercial operations. Now there are decades of installs that are ground down...I use CS 50A twist connectors and built two L14-50 to 50A CS adapters with cables going up, two with cables going down and the rest...found an L14-50 range plug with the cable coming straight out!
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(http://electrical-contractor.net/BCodes/condulet_recpt_1.JPG)
Shoot me now!!! :o
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i'll make this short.......NOT ! back in the 80's in california after the investigation it was determined that a paper clip had fallen behind a desk and landed on the hot and neutral prongs(blades) of a plug that was not plugged all the way into the receptical. the remains of the paper clip were still fused on it. the breaker didnt trip because its designed to trip when the max amount of amps is reached to protect the wire from overload. the prongs got hot and caught the plastic plug and wall plate on fire. wall paper and its flamable glue ignighted and a flash fire occured. several peope died. the code was changed in cali and required all recepticals installed form then on to have the ground hole up. it was thought that in a same or similar situation that a metal or conductive object would rotate off and fall to the floor. after years of tresting it was found that it wasnt the case and that many metalic objects rotated slow enought to fuse to the ground prong and the hot prong. so the code was changed again to allow recepticles to be installed with the ground hole in the bottom(sad) position. i am a commercial electrician.
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i'll make this short.......NOT ! back in the 80's in california after the investigation it was determined that a paper clip had fallen behind a desk and landed on the hot and neutral prongs(blades) of a plug that was not plugged all the way into the receptical.
Our UK plugs have a plastic cover on the live and neutral pins so this can't happen. Also stops inquisitive little fingers from getting a shock.
(http://www.ac-et.com/images/products/mkpf133blk.jpg)
Steve.
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Shoot me now!!! :o
How about this one. It has clearance for the Ground pin.
(http://lbpinc.com/NoStinkingGround.jpg)
Note, I collect these, I don't use them. Don't try this at home.
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Our UK plugs have a plastic cover on the live and neutral pins so this can't happen. Also stops inquisitive little fingers from getting a shock.
(http://www.ac-et.com/images/products/mkpf133blk.jpg)
Steve.
Ya, kind of wish the 5-15 connector would die. Your plug is the result of what happens when actual electrical safety is taken into account when designing a plug. It also does not hurt that at the time of design half of the UK needed to be re-wired anyway. So, adoption was easier.
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The nice thing about the UK plug is that for domestic use, it's the only one we have. Rather than have a variety of plugs to suit the various current requirements, ours is fitted with a 13 amp, 10 amp, 5 amp or 3 amp fuse as appropriate to the equipment it is connected to.
The original plug had solid brass contacts. The plastic sleeves were a later modification.
Steve.
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Most current electrical codes now call for the ground plug to be up...at least in commercial operations.
After having seen so many commercial construction sites with the ground installed up, I asked the builder of our new home why they weren't so in the house. He said, "You're thinking of commercial code. If you want, you can have an electrician flip them over after we're gone."
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Orientation of wall receptacles is not in the NEC code book, so it must be a local rule.
As a matter of fact over at the NEC code forum, receptacle orientation is a forbidden subject.
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Orientation of wall receptacles is not in the NEC code book, so it must be a local rule.
As a matter of fact over at the NEC code forum, receptacle orientation is a forbidden subject.
it was a california state code that was recinded several years ago. check out my reply on page 1 as to why the california building and departments enacted it. a city , state , etc and enact codes that go above and beyond the nec but they cannot do less the the nec. the nec is the minimun , not the maximum. example > conduit is required to be strapped/supported every 10 feet BUT a city/state can enact a code the requires conduit to be strapped/supported every 5 feet but they cannot enact a code that allows conduit to be supported every 11 feet.
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it was a california state code that was recinded several years ago. check out my reply on page 1 as to why the california building and departments enacted it. a city , state , etc and enact codes that go above and beyond the nec but they cannot do less the the nec. the nec is the minimun , not the maximum. example > conduit is required to be strapped/supported every 10 feet BUT a city/state can enact a code the requires conduit to be strapped/supported every 5 feet but they cannot enact a code that allows conduit to be supported every 11 feet.
Well, I must disagree. The NEC is a standard established by a non-governmental agency and, to my knowledge, it has not been adopted or mandated in federal legislation or regulation (except possibly for military installations). If a state or local regulatory agency chooses to adopt most of the NEC with modifications, they are free to do so. Those modification can include overriding portions of the Code, allowing greater minimums than the NFPA version of the Code allows. However, the state may require that any subordinate authorities consider the Code with the state's mods to be a minimum.
The purpose of my original post wasn't to drag a debate over the "best" orientation here, but to point out that the "best" orientation is often determined by the actual use rather than someone's idea of "safety."
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Well, I must disagree. The NEC is a standard established by a non-governmental agency and, to my knowledge, it has not been adopted or mandated in federal legislation or regulation (except possibly for military installations). If a state or local regulatory agency chooses to adopt most of the NEC with modifications, they are free to do so. Those modification can include overriding portions of the Code, allowing greater minimums than the NFPA version of the Code allows. However, the state may require that any subordinate authorities consider the Code with the state's mods to be a minimum.
The purpose of my original post wasn't to drag a debate over the "best" orientation here, but to point out that the "best" orientation is often determined by the actual use rather than someone's idea of "safety."
i really dont have a clue as to what you just said or why you quoted my post. i will tell that i have ben a commercial electrical for over 20 years, 15 as a "working forman" and over 8 as a certified journeyman. as for the state requiring more than the minimum we must do what they say or the electrical inspector will not do a final sign off the business will not be allowed to be occupied.
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i really dont have a clue as to what you just said or why you quoted my post. i will tell that i have ben a commercial electrical for over 20 years, 15 as a "working forman" and over 8 as a certified journeyman. as for the state requiring more than the minimum we must do what they say or the electrical inspector will not do a final sign off the business will not be allowed to be occupied.
Everybody please play nice. As is often the case, there is some truth on both sides of the argument. As I understand it, NFPA 70 (the National Electrical Code) does NOT have the power of federal law, much like each state can set its own speed limits and the feds can do little about it. I know for a fact that each state and county will pick when (and if) it will use the latest code book edition. And each state/county/city/inspector can choose if they will comply with everything in a particular edition of the code. For instance, there's a lot of dissension about requiring AFCI breakers in new builds. Now I'm not going to start up that particular debate in this thread (even though it would be interesting), but I know that some southern states have declared "states rights" and don't require their inspectors to require AFCI's. The reason they give is that the $300 additional cost of requiring AFCI breakers on a typical $100,000 build would create a hardship for the developers.
Also, as I've noted in a few other threads, there's a lot of code difference in each state and municipality. That's what makes ground loop chasing so difficult at times. You really don't know what you've got until you start looking at the details. That's one of the things I really like about this forum, you guys can offer examples of code in many states and even countries.
So now I want you all to kiss and make up or buy each other a beer (or whatever floats your boat).
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Everybody please play nice. As is often the case, there is some truth on both sides of the argument. As I understand it, NFPA 70 (the National Electrical Code) does NOT have the power of federal law, much like each state can set its own speed limits and the feds can do little about it. I know for a fact that each state and county will pick when (and if) it will use the latest code book edition. And each state/county/city/inspector can choose if they will comply with everything in a particular edition of the code. For instance, there's a lot of dissension about requiring AFCI breakers in new builds. Now I'm not going to start up that particular debate in this thread (even though it would be interesting), but I know that some southern states have declared "states rights" and don't require their inspectors to require AFCI's. The reason they give is that the $300 additional cost of requiring AFCI breakers on a typical $100,000 build would create a hardship for the developers.
Also, as I've noted in a few other threads, there's a lot of code difference in each state and municipality. That's what makes ground loop chasing so difficult at times. You really don't know what you've got until you start looking at the details. That's one of the things I really like about this forum, you guys can offer examples of code in many states and even countries.
So now I want you all to kiss and make up or buy each other a beer (or whatever floats your boat).
Exelent reply Mike. I had an inspector once that was making up his own code that went way beyond what was required. when he wanted me to add a 3rd ground wire i just looked at him with a "are you serious" look on my non smiley face at which point he told me i probably had enough service ground rods etc and signed off on the service. your not suppose to run overhead bare wire power either but the power company does it and the bare wires are usually 13,000+ volts depending on where you live.
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So now I want you all to kiss and make up or buy each other a beer (or whatever floats your boat).
Well, I don't drink and I kiss only my wife, so will a virtual handshake do?
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From a practical view, I have only seen (US) right angle plugs where the cable exits nearest the ground pin. To have the receptacle mounted with the ground pin on top would be very unstable.
Compare this to Steve's picture of a UK plug, where the cable exits between the L/N.
-Dennis
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From a practical view, I have only seen (US) right angle plugs where the cable exits nearest the ground pin. To have the receptacle mounted with the ground pin on top would be very unstable.
The US plugs go both ways.
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The US plugs go both ways.
It's fairly common for refrigerators in the US to have a right-angle plug with the cord exiting opposite the ground pin. But it's also fairly common for refrigerators to have it going the other way, too. There is no reliable rule-of-thumb; probably determined more by the manufacturer of the cordset than the assembler of the appliance.
Implementing partially-insulated prongs (like those in UK and EU) on US plugs probably wouldn't be a bad thing, but somewhere there is a receptacle this won't work in, and some manufacturer either of receptacles or cordsets will claim a hardship and thus stall implementation.
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The US plugs go both ways.
and more
(http://www.kordking.com/Images/products/offset-right-angle/ora-90-5-15p-full.jpg)
(http://jan.ucc.nau.edu/lrm22/learning_spaces/images/right_angle_plug.png)
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and more
(http://www.kordking.com/Images/products/offset-right-angle/ora-90-5-15p-full.jpg)
(http://jan.ucc.nau.edu/lrm22/learning_spaces/images/right_angle_plug.png)
working on a new angle aye ?
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(http://jan.ucc.nau.edu/lrm22/learning_spaces/images/right_angle_plug.png)
The nice thing about the diagonal one is that it is less likely to block another receptacle.
Now what would be nice is if they could make switching-type power adapters less like the typical wall wart and more long and slender so as to not block other receptacles, or to make a right-angle style with a swivel plug.
When power strips with "transformer-spaced" receptacles first appeared, many of them actually internally still had terminals in between the receptacles where they just removed the "holes" in the plastic injection mold. So they created a power strip with less functionality and marketed it as a new feature at a higher price. Ah, marketing.
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Just use this one-surely one will be the right one for your cord!
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Just use this one-surely one will be the right one for your cord!
I'm getting dizzy. :o
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Just use this one-surely one will be the right one for your cord!
I had those at a venue I use to work at. They were great on stage stringers. I could fit 4 wall warts at a time.
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These solve a lot of problems:
http://www.amazon.com/1-Feet-Outlet-Saver-Extension-5-Pack/dp/B00B728JY4
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Just use this one-surely one will be the right one for your cord!
i wonder how that would look spinning at 33-1/3 on the turntable