Re: stacking pdu

[Meagan]

Server tech makes some devices that are powered independently but can be 
managed as a single unit.  We have 2pdus per cabinet on separate circuits, 
which share a management controller and can provide stats for both circuits.


> On Jun 5, 2015, at 12:51 AM, shawn wilson  wrote:
> 
> Well, I was kinda thinking this would turn out to be a dumb question / have
> an obvious answer. Apparently not. But it seems I can't go buy a solution
> either. I guess there isn't much of a market (though I am just talking
> software - maybe someone could make an update :) ).
> 
> !DSPAM:55712b43141331257586274!
> 

Re: stacking pdu

[Eric Tykwinski]

I was pretty much thinking the same, get a switched/metered outlet PDU.  APC, 
ServerTech, et al have them, then daisy chain something like a Dell AP6015 off 
the outlet.  No clue about NEC/local laws, but the Dells are pretty much setup 
for that type of setup.

> On Jun 5, 2015, at 5:20 PM, Brian Loveland  wrote:
> 
> APC does make some 'half rack' PDU's that take a C20 inlet so they could
> hang off a C19 outlet on another PDU:
> http://www.apc.com/resource/include/techspec_index.cfm?base_sku=AP8858&displayList=ALL&page_type=displaybasic&printer_friendly=yes
> http://www.apc.com/resource/include/techspec_index.cfm?base_sku=AP7821&displayList=ALL&page_type=displaybasic&printer_friendly=yes
> 
> On the software side, just use a "master" PDU with metering.  These "sub"
> ones are also metered but you would want to look at the total utilization
> on the "master".
> 
> No comment if its to code...
> 
> On Fri, Jun 5, 2015 at 12:51 AM, shawn wilson  wrote:
> 
>> Well, I was kinda thinking this would turn out to be a dumb question / have
>> an obvious answer. Apparently not. But it seems I can't go buy a solution
>> either. I guess there isn't much of a market (though I am just talking
>> software - maybe someone could make an update :) ).
>> 

Re: stacking pdu

[Brian Loveland]

APC does make some 'half rack' PDU's that take a C20 inlet so they could
hang off a C19 outlet on another PDU:
http://www.apc.com/resource/include/techspec_index.cfm?base_sku=AP8858&displayList=ALL&page_type=displaybasic&printer_friendly=yes
http://www.apc.com/resource/include/techspec_index.cfm?base_sku=AP7821&displayList=ALL&page_type=displaybasic&printer_friendly=yes

On the software side, just use a "master" PDU with metering.  These "sub"
ones are also metered but you would want to look at the total utilization
on the "master".

No comment if its to code...

On Fri, Jun 5, 2015 at 12:51 AM, shawn wilson  wrote:

> Well, I was kinda thinking this would turn out to be a dumb question / have
> an obvious answer. Apparently not. But it seems I can't go buy a solution
> either. I guess there isn't much of a market (though I am just talking
> software - maybe someone could make an update :) ).
>

Re: stacking pdu

[Sean Donelan]

On Fri, 5 Jun 2015, Blake Hudson wrote:
The fire marshal that regularly inspects our building will cite us if he sees 
an extension cord in use - even temporarily - or sees a temporary power 
tap/surge suppressor connected to another. Meanwhile, in another city, I see 
government and commercial buildings violating these rules for years. Perhaps 
there's some amount of interpretation allowed or some inspectors are more 
aggressive than others.


Every Authority Having Jurisdiction (AHJ) is their own fiefdom.  Although
there are a few model national codes, its the locally enacted law and AHJ
interpretation that rules.

And, yes, the effectiveness and knowledge of AHJs varies greatly. It 
wouldn't surprise me if there were some places with no building codes

or inspectors.

Re: stacking pdu

[Stephen Satchell]

On 06/05/2015 11:47 AM, Blake Hudson wrote:

The fire marshal that regularly inspects our building will cite us if he
sees an extension cord in use - even temporarily - or sees a temporary
power tap/surge suppressor connected to another. Meanwhile, in another
city, I see government and commercial buildings violating these rules
for years. Perhaps there's some amount of interpretation allowed or some
inspectors are more aggressive than others.


Or the local ordinances block daisy-chaining.  I've run into this in 
several parts of the country, while other parts don't have local 
regulations -- particularly in "commercial" spaces, which include offices.

Re: stacking pdu

[William Herrin]

On Fri, Jun 5, 2015 at 2:47 PM, Blake Hudson  wrote:
>> William Herrin  writes:
>>> Isn't it against the NEC and the fire code to stack power strips? We
>>> all do it, but isn't it against code?
>
> The fire marshal that regularly inspects our building will cite us if he
> sees an extension cord in use - even temporarily - or sees a temporary power
> tap/surge suppressor connected to another.

I was dinged for power strips connected to a cube tap. I don't have
the citation handy, but I looked it up at the time and it was
definitely against code.

Regards,
Bill Herrin



-- 
William Herrin  her...@dirtside.com  b...@herrin.us
Owner, Dirtside Systems . Web: 

Re: stacking pdu

[Blake Hudson]

Rob Seastrom wrote on 6/4/2015 4:52 PM:

William Herrin  writes:


Isn't it against the NEC and the fire code to stack power strips? We
all do it, but isn't it against code?

...

As always, when someone asserts that "X is against code" whether in
the form of a statement or a question, the proper response is
"Citation, please!"

-r



The fire marshal that regularly inspects our building will cite us if he 
sees an extension cord in use - even temporarily - or sees a temporary 
power tap/surge suppressor connected to another. Meanwhile, in another 
city, I see government and commercial buildings violating these rules 
for years. Perhaps there's some amount of interpretation allowed or some 
inspectors are more aggressive than others.


--Blake

Re: stacking pdu

[shawn wilson]

Well, I was kinda thinking this would turn out to be a dumb question / have
an obvious answer. Apparently not. But it seems I can't go buy a solution
either. I guess there isn't much of a market (though I am just talking
software - maybe someone could make an update :) ).

Re: stacking pdu

[Matthew Petach]

On Thu, Jun 4, 2015 at 2:52 PM, Rob Seastrom  wrote:
>
...
> MC on thereifixed.com or similar sites).

thereifixedit.com

iftfy.  ;P

Matt

Re: stacking pdu

[Joe Hamelin]

This takes me back to the days of old with bread racks full of modems and
the mess of wall-warts and power-strips.

--
Joe Hamelin, W7COM, Tulalip, WA, 360-474-7474

On Thu, Jun 4, 2015 at 2:52 PM, Rob Seastrom  wrote:

>
> William Herrin  writes:
>
> > Isn't it against the NEC and the fire code to stack power strips? We
> > all do it, but isn't it against code?
>
> Sorry to be late to the party (I plead vacation), but no, afaik it is
> not.  About as close as the NEC comes art 400.8 - you can't use
> flexible cord as a substitute for permanent wiring (think of some of
> the shenanigans you've seen with extension cords standing in for NM or
> MC on thereifixed.com or similar sites).
>
> Rack wiring is not "permanent", but I would not go so far as to claim
> it is subject to the "qualified personnel" rules (OSHA subpart S and
> NFPA 70E).  Datacenter workers who could pass a test on LOTO
> procedures and routinely utilize proper PPE (even gloves, safety
> glasses, and steel toe shoes) are the exception rather than the rule.
>
> As always, when someone asserts that "X is against code" whether in
> the form of a statement or a question, the proper response is
> "Citation, please!"
>
> -r
>
>

Re: stacking pdu

[Rob Seastrom]

William Herrin  writes:

> Isn't it against the NEC and the fire code to stack power strips? We
> all do it, but isn't it against code?

Sorry to be late to the party (I plead vacation), but no, afaik it is
not.  About as close as the NEC comes art 400.8 - you can't use
flexible cord as a substitute for permanent wiring (think of some of
the shenanigans you've seen with extension cords standing in for NM or
MC on thereifixed.com or similar sites).

Rack wiring is not "permanent", but I would not go so far as to claim
it is subject to the "qualified personnel" rules (OSHA subpart S and
NFPA 70E).  Datacenter workers who could pass a test on LOTO
procedures and routinely utilize proper PPE (even gloves, safety
glasses, and steel toe shoes) are the exception rather than the rule.

As always, when someone asserts that "X is against code" whether in
the form of a statement or a question, the proper response is
"Citation, please!"

-r

Re: stacking pdu

[Owen DeLong]

> On May 29, 2015, at 2:48 PM, Brandon Martin  wrote:
> 
> On 05/29/2015 05:29 PM, William Herrin wrote:
>> On Fri, May 29, 2015 at 4:32 PM, shawn wilson  wrote:
>>> Is there a way to stack PDUs? like, with 30A 220, we need more plugs
>>> than power but I'd like them to communicate to make sure we don't over
>>> power the circuit. Do any APC or Triplite systems support this?
>> 
>> Isn't it against the NEC and the fire code to stack power strips? We
>> all do it, but isn't it against code?
> 
> It sounds like he's asking for a PDU specifically intended to be used with 
> managed expansion/stacking type modules.  That would be permissible per NEC 
> and most local fire codes as the device would be specifically listed for such 
> usage.  I've seen something like this inside blade/modular racks like IBM 
> Flex systems, but unfortunately I don't know of any such off-the-shelf parts.
> 
> It would seem entirely reasonable to take a 30A/240V feed on a 6-30 or 14-30 
> type connection and break it out to numerous either C13 or 6-15/5-15 style 
> sockets, possibly on a modular basis using some sort of proprietary 
> power+data connections for the breakout.  E.g. if you needed to mix 120V and 
> 240V devices in a rack, you could get 5-15 and 6-15 breakouts with each 
> individual outlet switched and maintain whole-rack metering.
> 
> Sounds like a really handy device, if one exists COTS.
> -- 
> Brandon Martin

If I read it correctly, stacking PDUs is perfectly acceptable so long as the 
breaker feeding each subordinate PDU is sized no larger than the maximum 
current that can be safely delivered to that PDU.

However, adding extension cords or other “temporary power extenders” on a 
permanent basis is also unacceptable and most PDU stacking of the type being 
contemplated here involves deploying the subordinate PDU in a way that ends up 
being essentially an “extension cord” for this purpose.

Owen

Re: stacking pdu

[Rafael Possamai]

You could run a PDU in paralallel so that you don't use more current than
the wires are rated for (although the PDU should trip the circuti anyways
in case you overload it). Only problem is matching the receptacles. You
probably don't want to half-ass it, so I'd just add an extra PDU and run an
extra ethernet cable so you can monitor it.

On Fri, May 29, 2015 at 4:29 PM, William Herrin  wrote:

> On Fri, May 29, 2015 at 4:32 PM, shawn wilson  wrote:
> > Is there a way to stack PDUs? like, with 30A 220, we need more plugs
> > than power but I'd like them to communicate to make sure we don't over
> > power the circuit. Do any APC or Triplite systems support this?
>
> Isn't it against the NEC and the fire code to stack power strips? We
> all do it, but isn't it against code?
>
> Regards,
> Bill Herrin
>
> --
> William Herrin  her...@dirtside.com  b...@herrin.us
> Owner, Dirtside Systems . Web: 
>

Re: stacking pdu

[Brandon Martin]

On 05/29/2015 05:29 PM, William Herrin wrote:

On Fri, May 29, 2015 at 4:32 PM, shawn wilson  wrote:

Is there a way to stack PDUs? like, with 30A 220, we need more plugs
than power but I'd like them to communicate to make sure we don't over
power the circuit. Do any APC or Triplite systems support this?


Isn't it against the NEC and the fire code to stack power strips? We
all do it, but isn't it against code?


It sounds like he's asking for a PDU specifically intended to be used 
with managed expansion/stacking type modules.  That would be permissible 
per NEC and most local fire codes as the device would be specifically 
listed for such usage.  I've seen something like this inside 
blade/modular racks like IBM Flex systems, but unfortunately I don't 
know of any such off-the-shelf parts.


It would seem entirely reasonable to take a 30A/240V feed on a 6-30 or 
14-30 type connection and break it out to numerous either C13 or 
6-15/5-15 style sockets, possibly on a modular basis using some sort of 
proprietary power+data connections for the breakout.  E.g. if you needed 
to mix 120V and 240V devices in a rack, you could get 5-15 and 6-15 
breakouts with each individual outlet switched and maintain whole-rack 
metering.


Sounds like a really handy device, if one exists COTS.
--
Brandon Martin

Re: stacking pdu

[William Herrin]

On Fri, May 29, 2015 at 4:32 PM, shawn wilson  wrote:
> Is there a way to stack PDUs? like, with 30A 220, we need more plugs
> than power but I'd like them to communicate to make sure we don't over
> power the circuit. Do any APC or Triplite systems support this?

Isn't it against the NEC and the fire code to stack power strips? We
all do it, but isn't it against code?

Regards,
Bill Herrin

-- 
William Herrin  her...@dirtside.com  b...@herrin.us
Owner, Dirtside Systems . Web: 

Re: stacking pdu

[Jason Biel]

How many plugs and what style do you need?  What is the facility
providing receptacle wise?  L15-30A three-phase ?



> On May 29, 2015, at 10:34 PM, shawn wilson  wrote:
>
> Is there a way to stack PDUs? like, with 30A 220, we need more plugs
> than power but I'd like them to communicate to make sure we don't over
> power the circuit. Do any APC or Triplite systems support this?

stacking pdu

[shawn wilson]

Is there a way to stack PDUs? like, with 30A 220, we need more plugs
than power but I'd like them to communicate to make sure we don't over
power the circuit. Do any APC or Triplite systems support this?