'single outlet' vs. duplex receptacle

[milemaker13]

Hey Gang-
My company is trying to become more safety minded. We have a lady that is in charge of addressing the safety concerns around the facility.

Here is the current topic of discussion: Plugging power strips into outlets. She says that there should not be two power strips plugged into a single outlet and has some poorly written internet research to back her up.

Her info states that power strips should not be piggybacked. Nor should they be plugged into a "multiple plug adaptor". I agree to both of these.

She is taking this to mean that you cannot plug two power strips into a duplex receptacle (one in each outlet). I'm not sure I agree.

My thinking: A 15 amp duplex receptacle is capable of 15 amps per side, since you could plug a 15 amp appliance into one side. The circuit is only capable of 15 amps per the breaker installed, thus preventing an overload if two 15 amp appliances are plugged in (one in each side of receptacle). I would think a "power strip" is considered a single "appliance", especially considering it has is own overcurrent protection. Therefore, two power strips plugged into a duplex receptacle (one in each side) would be acceptacle.

The issue comes up in the office area where everyone has multiple plugs for all the electronic gizmos now common in everyday life.

 

[milemaker13]

I'm just looking for clarification on the topic for my own knowledge. I don't want to challange the safety lady. :happyno: That would be a No- No!

 

[Smart $]

IMO, these are not safety concerns, but rather usages which are more prone to have issues. More directly the true concerns are poor receptacle retention and blade contact, plugs with broken or loose grounding blades, cord jackets receded from plugs indicating pulled out with cord rather than plug; compromised cord insulation and/or conductors.

 

[al hildenbrand]

Here is the current topic of discussion: Plugging power strips into outlets. She says that there should not be two power strips plugged into a single outlet . . .

Without having read or heard the points explained by the Safety Person, and just taking the topic as you've given it to us in your opening post, I would submit that there is a conflation of two different things.

Take a look at the Article 100 Definitions of Outlet, Receptacle Outlet, Receptacle and Device. Of the four, Outlet is the only one that is a "point". While a Receptacle Outlet is an Outlet, not all Outlets are Receptacle Outlets. Outlets are also Lighting Outlets and just plain old Outlets.

Common slang would have us equate a Receptacle with Outlet, but the terms are not equal to each other.

One plugs a power strip into a receptacle at an outlet. The receptacle, being a manufactured device, has ratings given to it by its manufacturer in conformance with its UL standard. The Safety Person needs to be guided to the published ratings of each receptacle of a duplex receptacle.

The Safety Person is saying it is "unsafe" to plug individual power strips into each NEMA 15 receptacle of a duplex receptacle. So, if only one receptacle can be used, which receptacle of a duplex is the "safe" receptacle as demonstrated by all the manufacturer's standards? It can't be done. The receptacles are equally safe.

The challenge for the Safety Person is to demonstrate which receptacle is the "safe" receptacle to use. In a collection of NEMA 15 receptacles (National Electrical Manufacturer Association) that are under one cover plate, NEMA 15 receptacles that are rated by the manufacturers to the same standard, one simply can't "technically" distinguish one as being different from any other.

The discussion topic is fatally flawed in its very language, and, therefore, in my opinion, is a truly great impetus for a learning point and a great discussion.

 

[GOZ]

Is she suggesting that all Duplex outlets be changed to single? If so, You still potentially have the same issue that she is concerned about. I would have to politely challenger her. I run into the same things with our safety coordinator at my facility. As an unwritten rule of thumb. I limit to 10 outlets per circuit. Good luck.

 

[Sierrasparky]

The issue is not a code issue. You can have a device plugged into each and every receptacle. No code that limits plug strip devices.
However one should be concerned that there is sufficient circuits for the usage as well as sufficient outlets dispursed throught so that extension cords are not used in lieu of permanent wireing.
Once again not a code issue as you describe.

 

[milemaker13]

I think you guys are right when you suggest it is a language issue. The info she provided, if read correctly, doesn't back her up. Actually, it doesn't say anything about this particular subject. Go figure..

But what she is saying is that two power strips should not be plugged into a duplex receptical.

I think that if she persues the issue, I will have to politely educate her on the differance between an outlet and a receptacle. We are just starting this safety program, so there will be plenty of time for polite discussion. :slaphead:

Thanks guys. This board is always helpful.:thumbsup:

 

[Sierrasparky]

Glad to help any time

add more confusion too:happyno:

 

[GoldDigger]

I think you guys are right when you suggest it is a language issue. The info she provided, if read correctly, doesn't back her up. Actually, it doesn't say anything about this particular subject. Go figure..

But what she is saying is that two power strips should not be plugged into a duplex receptical.

I think that if she persues the issue, I will have to politely educate her on the differance between an outlet and a receptacle. We are just starting this safety program, so there will be plenty of time for polite discussion. :slaphead:

Thanks guys. This board is always helpful.:thumbsup:

On the other hand, the listing conditions and use instructions for most if not all power strips prohibit plugging one power strip into another to extend the distance or provide more receptacles. That is done just as often as plugging two strips into one duplex receptacle and is arguably less safe.
When using cube taps or other compact receptacle multiplexers there can be a problem of heat dissipation from multiple poor connections. A duplex receptacle is less likely to overheat than a cube tap, especially since you do not have two contact resistances in series in the same small physical device.

 

[milemaker13]

The info she came up with does say it isn't a good idea to daisy chain the power strips, or to use a multiple plug adapter (like in 'a christmas story', lol). But it is more concerned with the jostling and poor connections. Again, I agree.

 

[al hildenbrand]

On the other hand, the listing conditions and use instructions for most if not all power strips prohibit plugging one power strip into another to extend the distance or provide more receptacles.

:thumbsup:

Indeed. And, even if the instructions are not clear, or absent, the so-called UL White Book describes the common power strip as a "relocatable power tap" and gives it the designation Category XBYS. There are a bunch of instructions. This is where the "truth" comes from that is beyond the NEC. (Note that "directly connected to a . . . receptacle" is not "outlet" nor is it allowing a multiple plug adapter.

Relocatable power taps are intended to be directly connected to a permanently installed branch circuit receptacle.

Relocatable power taps are not intended to be series connected (daisy chained) to other relocatable power taps or to extension cords.

Relocatable power taps are not intended for use at construction sites and similar locations.

Relocatable power taps are not intended to be permanently secured to building structures, tables, work benches or similar structures, nor are they intended to be used as a substitute for fixed wiring. The cords of relocatable power taps are not intended to be routed through walls, windows, ceilings, floors or similar openings.

The length of the power-supply cord, as measured from the outside surface of the enclosure of the relocatable power tap to the plane of the face of the attachment plug, should not exceed 25 ft (7.62 m) nor be less than 1.5 ft (0.46 m).