T-slot plugs and 20 amp appliances?

Not if using shunt protectors. The equipment must be on the same circuit, but can be fed through multiple receptacles, and you can install multiple shunt type protectors. A single point of use protector is often impractical/impossible for multiple pieces of equipment. That may not be an ideal situation, but it is nonetheless a common occurence.

Ed

Reply to
ehsjr
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Multiple circuits also prevent the complete shutdown of all the servers if there is an electrical fault in a server room. Some headends had six 120 V, 20 A circuits for the electronics, and a 240 V, 20 A circuit for the room's air conditioner.

Reply to
Michael A. Terrell

I have seen a commercial/industrial power strip that had a few 6-15R duplex recepticles, at the same company where I got the workbench. No good for 120V devices since 6-15R recepticles have no neutral. I don't remember what sort of plug its cord had.

A regular consumer-grade power strip (not the one in my workbench) rated for 20A and a regular 5-20P would be useful for people with larger setups. They probably don't exist for residential service simply because many people would buy them by mistake not seeing/knowing about the plug, and either return it or replace the plug and overload a 15A circuit, and relatively few will wind up being used properly.

The fact all consumer-grade power strips have a switch and a 15A breaker tells me that regulations somehow consider them different from "extension cords" which can also easily be overloaded even if all devices plugged into them use less than the rated current of a 5-15P plug.

Reply to
Michael Moroney

| Not if using shunt protectors. The equipment must be on the | same circuit, but can be fed through multiple receptacles, and | you can install multiple shunt type protectors. A single | point of use protector is often impractical/impossible for | multiple pieces of equipment. That may not be an ideal | situation, but it is nonetheless a common occurence.

Where the supply wires break apart determines the degree of induced difference voltage. The closer to the equipment this is, the less the difference. And the use of a common protector closer to the equipment helps ensure a minimum difference.

It's a matter of degree. And I want it all.

Reply to
phil-news-nospam

On Sun, 01 Jun 2008 23:02:14 -0400 Michael A. Terrell wrote: | | ehsjr wrote: |> |> snipped-for-privacy@ipal.net wrote: |> > On Sat, 31 May 2008 23:44:50 -0400 Michael A. Terrell wrote: |> > | snipped-for-privacy@aol.com wrote: |> > |>

|> > |> On 31 May 2008 10:45:59 GMT, snipped-for-privacy@ipal.net wrote: |> > |>

|> > |> >So what would you use for a group of computers that need to be connected to |> > |> >power from a single outlet for maximum protection, which use more than the |> > |> >current allowed on a 5-15P plug? |> > |>

|> > |> 6-15 power cords and switch the PS to 240v |> > | |> > | |> > | |> > | Or multiple 120 VAC circuits, like we do in broadcast studios and |> > | CATV headends. |> >

|> > I want common surge protection on the metallically interconnected computers. |> > So it all needs to come off a single outlet and go through a single surge |> > protector. |> |> Not if using shunt protectors. The equipment must be on the |> same circuit, but can be fed through multiple receptacles, and |> you can install multiple shunt type protectors. A single |> point of use protector is often impractical/impossible for |> multiple pieces of equipment. That may not be an ideal |> situation, but it is nonetheless a common occurence. | | | Multiple circuits also prevent the complete shutdown of all the | servers if there is an electrical fault in a server room. Some headends | had six 120 V, 20 A circuits for the electronics, and a 240 V, 20 A | circuit for the room's air conditioner.

Where things go to the extreme that multiple circuits cannot be avoided then you have to deal with that. But where the scale is still small enough to be done with a single circuit, then it should be.

This is for a home server room. It's not mission critical. If a 20A or 30A

240V or 120/240V circuit is sufficient, then why not. Keep in mind that all PCs these days are fully able to operate directly from 240V. Lots of wall warts can be had that will as well (though in many cases you may have to get the Europe versions). What little remains that still needs 120V can be fed through a small stepdown transformer.
Reply to
phil-news-nospam

On Mon, 2 Jun 2008 15:30:57 +0000 (UTC) Michael Moroney wrote: | snipped-for-privacy@ipal.net writes: | |>On Sat, 31 May 2008 23:20:53 -0400 snipped-for-privacy@aol.com wrote: |>| On 31 May 2008 10:45:59 GMT, snipped-for-privacy@ipal.net wrote: |>| |>|>So what would you use for a group of computers that need to be connected to |>|>power from a single outlet for maximum protection, which use more than the |>|>current allowed on a 5-15P plug? |>| |>| 6-15 power cords and switch the PS to 240v | |>Power strips and point of use surge protectors for 240v circuits that are 120v |>relative to ground are definitely hard to find and may not even exist. Do you |>know of any? | | I have seen a commercial/industrial power strip that had a few 6-15R | duplex recepticles, at the same company where I got the workbench. | No good for 120V devices since 6-15R recepticles have no neutral. I | don't remember what sort of plug its cord had.

If I had one of those, it would just be run at 240V and the lack of neutral would not be a problem.

|>I have seen a power strip / surge protector with L5-20P plug and 5-15R outlets. | | A regular consumer-grade power strip (not the one in my workbench) rated | for 20A and a regular 5-20P would be useful for people with larger setups. | They probably don't exist for residential service simply because many | people would buy them by mistake not seeing/knowing about the plug, and | either return it or replace the plug and overload a 15A circuit, and | relatively few will wind up being used properly.

If they have a power demand that exceeds a 15A circuit, putting it all on a

15A circuit is a bad thing regardless of whether the power strip is the right type or not. Still, it can make for less safe usage when people cut off the plug and insert their own.

I have seen a 5-20P -> multiple 5-15R strip. It was presumably intended for the larger cases of usage. Maybe they also make a 5-20P -> multiple 5-20R or even 5-20P -> multiple 5-20RALT.

But what I want is the 6-15P or 6-20P strip that has 6-15R or 6-20R outlets. I'd rather have that over the readily available Schuko strips because the surge protection within could be correct with respect to the voltage clamp level for the conductor to ground MOVs (needs to be based on 120V supply as in North America rather the 230V supply as in Europe).

| The fact all consumer-grade power strips have a switch and a 15A breaker | tells me that regulations somehow consider them different from "extension | cords" which can also easily be overloaded even if all devices plugged | into them use less than the rated current of a 5-15P plug.

I still occaisionally see some that do not have the switch/breaker.

I will need to investigate the usability of the "whole house" panel protectors (the kind that plug into 2 or 4 breaker panel slots) for computer rack.

Reply to
phil-news-nospam

FWIW,I just saw an old (1946) Sylvester/Tweety Bird cartoon and it showed one of these T slot duplex outlets. What was odd was the outlet faces were rotated 90 degrees, which I've never seen in a real outlet.

Reply to
Michael Moroney

| snipped-for-privacy@ipal.net writes: | |>The legacy T-slot outlet was an ungrounded outlet that had the T-slot hole |>for both conductors. I still occaisionally see them around on very old |>wiring. The intent was to be a single product usable for either 120V or |>240V circuits. You can see the risks it exposed. It would not be allowed |>today, and may not have ever been technically allowed. | | FWIW,I just saw an old (1946) Sylvester/Tweety Bird cartoon and it showed | one of these T slot duplex outlets. What was odd was the outlet faces | were rotated 90 degrees, which I've never seen in a real outlet.

I don't follow what kind of rotation this was. There are some possibilities that I can imagine:

  1. The whole duplex was rotated, making each of the two outlets left and right of each other. The ends of the T's are up and down.

  1. Each of the 2 outlets was independently rotated, while remaining one above the others. The ends of the T's are up and down.

  2. Just the T's themselves are rotated. That would look weird.

  1. A combination of rotating the duplex and rotating the outlets. This would have left and right outlets, but leaving the ends of the T's sideways as they were before.

See also:

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Reply to
phil-news-nospam

In an old book on wiring I saw a picture of a duplex outlet used for DC

- it also had a T-slot but had the t and straight slot arranged vertically. No ground pin, of course. I've never seen anything that described standards for DC wiring - I suspect any books on that would be before WWII at least.

Bill ( Just when did Toronto have DC distribution, any way? I know DC hung on in a small way in New York until just a few months ago - but I was never aware there was much DC central station power in Canada. )

Reply to
Bill Shymanski

I'm not sure I understand what #3 is, but what I meant is #2. The outlets are one above the other the way most are currently, but a normal flat blade (120V) plug would go in with the blades horizontal, one above the other.

Like this:

| ---

--- |

| ---

--- |

I think I saw another outlet like this in another cartoon but mounted horizontally, thus like #4. It was a while ago that I saw that.

Another odd one we had when I was a kid. A combination outlet/faceplate that had 5 two blade outlets in a normal duplex box size. Yes they all (barely) fit! You could only plug the smaller lamp cord plugs in if you wanted to use them all. I wish I kept it when the neighbors renovated the place (we moved next door). This just had the vertical slots, no T slots. Obviously no ground pins (no room!).

Reply to
Michael Moroney

I took out one that had 3 in one. I had never seen that before. No grounds of course. Eric

Reply to
Eric

| In an old book on wiring I saw a picture of a duplex outlet used for DC | - it also had a T-slot but had the t and straight slot arranged | vertically. No ground pin, of course. I've never seen anything that | described standards for DC wiring - I suspect any books on that would be | before WWII at least.

And a book that old would very likely be unrelated to today's standards on safety.

Reply to
phil-news-nospam

On Thu, 5 Jun 2008 02:04:31 +0000 (UTC) Michael Moroney wrote: | snipped-for-privacy@ipal.net writes: | |>On Wed, 4 Jun 2008 15:52:24 +0000 (UTC) Michael Moroney wrote: | |>| FWIW,I just saw an old (1946) Sylvester/Tweety Bird cartoon and it showed |>| one of these T slot duplex outlets. What was odd was the outlet faces |>| were rotated 90 degrees, which I've never seen in a real outlet. | |>I don't follow what kind of rotation this was. There are some possibilities |>that I can imagine: | |>1. The whole duplex was rotated, making each of the two outlets left and right |> of each other. The ends of the T's are up and down. | |>2. Each of the 2 outlets was independently rotated, while remaining one above |> the others. The ends of the T's are up and down. | |>3. Just the T's themselves are rotated. That would look weird. | |>4. A combination of rotating the duplex and rotating the outlets. This would |> have left and right outlets, but leaving the ends of the T's sideways as |> they were before. | | I'm not sure I understand what #3 is, but what I meant is #2. The | outlets are one above the other the way most are currently, but a normal | flat blade (120V) plug would go in with the blades horizontal, one above | the other. | | Like this: | | | | --- | | --- | | | | | | | --- | | --- | |

I do recall seeing an outlet oriented like that, but it was a single not a duplex. But a duplex would be entirely plausible as increased use of this new-fangled electricity took place.

| I think I saw another outlet like this in another cartoon but mounted | horizontally, thus like #4. It was a while ago that I saw that.

Mounting outlets horizontally, so one is left or right of the other, is common in Europe. I see advantages to it and would like to do that for my home. But I still want the ground pin on the up side, not left or right.

| Another odd one we had when I was a kid. A combination outlet/faceplate | that had 5 two blade outlets in a normal duplex box size. Yes they all | (barely) fit! You could only plug the smaller lamp cord plugs in if | you wanted to use them all. I wish I kept it when the neighbors | renovated the place (we moved next door). This just had the vertical | slots, no T slots. Obviously no ground pins (no room!).

I remember seeing something somewhat like that once. It had 2 very LONG slots and you could squeeze in more plugs if they were thin. No ground.

Reply to
phil-news-nospam

|> Another odd one we had when I was a kid. A combination outlet/faceplate |> that had 5 two blade outlets in a normal duplex box size. Yes they all |> (barely) fit! You could only plug the smaller lamp cord plugs in if |> you wanted to use them all. I wish I kept it when the neighbors |> renovated the place (we moved next door). This just had the vertical |> slots, no T slots. Obviously no ground pins (no room!). | I took out one that had 3 in one. I had never seen that before. No | grounds of course.

Something like this?

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Reply to
phil-news-nospam

These are the same people who brought you the Acme rocket powered roller skates.

Reply to
gfretwell

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Yeah the cover plate was like that. Hell, I once had an outlet strip that had no slots at all, just 2 continuous grooves. Seemed sort of dangerous.. Eric

Reply to
Eric

They were, when they got old. They didn't hold the plugs tight, and overheated, like any other worn outlet. That crap was common on benches in TV & radio repair shops in the '60s & '70s.

Reply to
Michael A. Terrell

I've got one of those; I've also seen a 20A version, with a 5-20R and a 6-20R.

I have seen a 7-15R, but I cannot remember where. I've never seen the

347V version, but then I don't think I've ever seen a 347/600V installation.
Reply to
furles

I happened to see a real but newer outlet like that (actually about 4 of them), older GFI outlets with one outlet above the others, but rotated so that the ground pins were on the left. The test buttons were between the outlets like other GFI outlets.

Reply to
Michael Moroney

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