I really want to move all newly installed internal and customer racks
over to all 208v power instead of 120v. As far as I can remember, I
can't remember any server/switch/router or any other equipment that
didn't run on 208v AC. (Other than you may need a different cable)
Anyone have any experience where some oddball equipment that couldn't
do 208v and regret going 208v? We won't have any TDM or SONET
equipment, all Ethernet switches, routers and servers. I have control
over internal equipment but sometimes customers surprises you.
Hi Jay,
Pretty much any little oddball piece of equipment with an external
power brick is at risk. The hundred buck ethernet-based USB extender
was my particular lesson.
If you're talking about paying customers who bring in their own
equipment, you'll run in to this a *lot*.
Regards,
Bill Herrin
Dear Jay,
I really want to move all newly installed internal and customer racks
over to all 208v power instead of 120v. As far as I can remember, I
can't remember any server/switch/router or any other equipment that
didn't run on 208v AC. (Other than you may need a different cable)
Anyone have any experience where some oddball equipment that couldn't
do 208v and regret going 208v? We won't have any TDM or SONET
equipment, all Ethernet switches, routers and servers. I have control
over internal equipment but sometimes customers surprises you.
you mean 240V AC 50HZ and move from 120V 60Hz? (or also 50Hz)
you will need to check each device if it supports 240V, commonly the specified power ratings are printed at a stricker on the device itself.
Kind regards,
Ingo Flaschberger
you mean 240V AC 50HZ and move from 120V 60Hz? (or also 50Hz)
In US, I think everything is 60Hz. But I mean 208v single phase.
(Which is what you get when you combine two 120v single phase legs out
of three phase, I believe. I am not an expert on AC...)
you will need to check each device if it supports 240V, commonly the
specified power ratings are printed at a stricker on the device itself.
I have even been looking at USB HD AC adapter and all other odd ball
equipment and I always see the label say "100~240v AC". Dell's old
rack mount monitor/KB from 5 years ago even supports 208v (Just wrong
connector.)
No, I'm pretty sure he means "across the 2 high legs of a 120/208 3ph
Wye service", and I'd never heard that idea suggested before. I can see
why it reduces the amount of copper you need to run, but it seems as if
it would have compensating disadvantages, though I can't think precisely
what they might be at the moment.
-- jra
Probably not; 208V AC here in the US comes from 3-phase distribution systems and is relatively common in datacenters, as well as other commerical and industrial settings.
What we've done is to install one 120V, 15A circuit per rack along with the 2x or 4x 208V 30A circuits. There are too many oddball and/or just plain old devices out there to go totally without. Like another commenter mentioned, the prime offender these days are devices with external power bricks or wall-warts; often times they only have NEMA 5-15 plugs so at least there won't be temptation to stick them in 208V receptacles.
Assuming you go with IEC C-13 or C-19 receptacles for those 208V circuits, that is.
Just be careful on older non-autosensing power supplies where you have to flip a switch to go from 100-120V to 200-240V input, in that you make sure to flip them to begin with, and that you flip them back should you ever mover them back to a 120V circuit.
you mean 240V AC 50HZ and move from 120V 60Hz? (or also 50Hz)
In US, I think everything is 60Hz. But I mean 208v single phase.
(Which is what you get when you combine two 120v single phase legs out
of three phase, I believe. I am not an expert on AC...)
Correct, a L-N connection will get you 120V, a L-L connection will get
you 208V. Everything in the US is 60Hz.
you will need to check each device if it supports 240V, commonly the
specified power ratings are printed at a stricker on the device itself.I have even been looking at USB HD AC adapter and all other odd ball
equipment and I always see the label say "100~240v AC". Dell's old
rack mount monitor/KB from 5 years ago even supports 208v (Just wrong
connector.)
The vast majority of power adapters are switching these days and will
run up to 240, it's when they have built in NEMA 1-15 or 5-15 prongs
that you have to overcome.
~Seth
I once had a cage that was all 220v. Wasn't an issue at all. Had two
devices that required some effort to work around...
1. A small media converter. This was powered by a wall-wart style
power supply that fed it 12v DC, but, the wall wart that shipped
with it did not handle 220v. No regret, but, a quick trip to Fry's
to buy a suitable universal wall-wart with 220v capability and
problem solved.
2. Our cordless screwdriver charger would not accept 220v.
Initially, we just plugged it into an outlet in the customer work
area whenever we were at the datacenter. Long term solution,
we bought one of those international transformers and
hooked it up that way.
I think we might have built some of our own adapter cables to
deal with plug issues, but, it's pretty easy to build 3-wire pigtail
converters and Home Despot has all the necessary supplies.
Owen
Hi Ingo,
208 and 480 both at 60 hz are common three-phase voltages available in
commercial buildings in North America. 208 is three hot conductors 120
degrees out of phase with each other, each 120 volts to common. 480 is
the same but with 277 volts to common. 208 is often used with
higher-wattage computing equipment while 480 is usually used for
distribution on the input side of a large UPS and for lighting.
Another thought for you Jay - if you deliver L21 series receptacles to
the cabinet (5 wires) the customer can employ it as 120vac, 208vac or
a mix as they choose, though you will have to facilitate plug
converters for their PDUs. Also mixing on the same circuit complicates
amperage estimating something fierce unless the use at one of the
voltages is trivial.
Regards,
Bill Herrin
In a message written on Thu, Dec 02, 2010 at 11:32:16AM -0500, Jay Ashworth wrote:
No, I'm pretty sure he means "across the 2 high legs of a 120/208 3ph
Wye service", and I'd never heard that idea suggested before. I can see
why it reduces the amount of copper you need to run, but it seems as if
it would have compensating disadvantages, though I can't think precisely
what they might be at the moment.
In most residential / small business construction in the US you
will find "240V single phase with neutral". There are two hot wires
and a neutral from the provider. Hot to hot is 240, hot to neutral
is 120.
Most colos run their back end plant (e.g. UPS's, Gensets, etc) on
480v 3-phase power. The typical way they get 120v power is to
transform that to a 3-phase Y wired output, also known as 3-phase
4 wire. Each hot leg is 120v to the neutral (the fourth wire).
You can run hot to hot here as well, where the voltage is 208v.
The trick with 208v loads in this situation is you want to keep the
load across each pair of phases roughly balanced.
What can be particularly confusiong here is the panels look exactly
the same. The same physical panel layout your house gets with 2
phases in plus a neutral is now two of the three phases from the
three phase power go in, plus a neutral. Same breakers are used,
with hot to hot being 208 volt. The difference is, in the colo
there are three of them:
A N B B N C C N A
> > > > > > > > >
Panel 1 Panel 2 Panel 3
With A, B, and C being the 3 phases, and N being the neutral.
You may also find this arrangement in larger multi-tennent buildings
where they are fed with 3-phase power.
Dear Jay,
you mean 240V AC 50HZ and move from 120V 60Hz? (or also 50Hz)
In US, I think everything is 60Hz. But I mean 208v single phase.
(Which is what you get when you combine two 120v single phase legs out
of three phase, I believe. I am not an expert on AC...)
I got the point.
120 * sqrt(3), phase to phase, three-phase current in european;
you will need to check each device if it supports 240V, commonly the
specified power ratings are printed at a stricker on the device itself.I have even been looking at USB HD AC adapter and all other odd ball
equipment and I always see the label say "100~240v AC". Dell's old
rack mount monitor/KB from 5 years ago even supports 208v (Just wrong
connector.)
Whats the idea behind todo this?
You will also need circuit breakers that both phases are switched of
simultaneous?
Kind regards,
Ingo Flaschberger
Wall wart supplies will need changing, more than likely.
I have a few racks with 208V distribution (EMC 40U racks are built this way), and haven't run into many issues. But you do need to watch carefully, and whatever you do do not wire a 5-15R or 5-20R (or any other '5-' receptable or 'L5-' receptacle) to 208; use the proper '6-' receptacles or IEC receptacles (as mentioned) for all 208 power. This is typically mandated by NEC in new installations, and the electrician doing the distribution should be familiar with the NEMA connector chart. See https://secure.wikimedia.org/wikipedia/en/wiki/NEMA_connector for more information on those connectors.
Also, if your customers provide their own UPS equipment that could be an issue, as very few UPS I'm aware of are multi-voltage input (APC SmartUPS 3000 is what I use typically, and that by default needs an L5-30R).
But if you provide a neutral with your 208 (using an L14 connector) you then can have mixed distribution with 120V available on 5-15R's but 208 receptacles for major power consumers in the rack. That's what I've done in most of my racks that need 208 (like for 7609's and Cisco 12K), other than the EMC's, which use L6-30's for the rack input, and IEC receptacles for the devices in the rack.
It is not uncommon for three-phase panels to be different and have
all three phases in the panel each phase feeding every third breaker
slot.
Owen
Biggest issue we see with people still needing 120V outlets is external modems for out of band access. Most of the time these modems are attached to the console of carrier managed routers.
Or as others in the thread have mentioned, wall-warts for things like USB hard drives, low-end KVMs, etc often are NEMA 5-15P plugs hardwired to them. ASA5505s have this problem with the cable as well, but their power supplies will work on 208V with the necessary adapter.
Jeremy
No, I'm pretty sure he means "across the 2 high legs of a 120/208 3ph
Wye service", and I'd never heard that idea suggested before. I can see
why it reduces the amount of copper you need to run, but it seems as if
it would have compensating disadvantages, though I can't think precisely
what they might be at the moment.
The only ones I can think of are relatively modest, such as needing 2-pole breakers or a pair of ganged single-pole breakers for each circuit, so a panelboard would only be able to support half as many 208V circuits as 120V circuits.
That could translate into needing more panelboards, more/larger switchgear to feed those panelboards, etc, but you can plan for this up-front easily enough if this new construction or a re-fit of an existing space.
The panelboards we put in our DR site last year are quite large, so we have some room to grow, and we also used 3-phase PDUs with both 120V and 208V receptacles, there are fewer individual circuits going out to each cabinet.
jms
Been there, done that with my nagios box when I had to replace a fan
years ago. The build table was 120V so I flipped the switch and forgot
to flip it back. It actually booted for about 5 seconds before things
inside the PSU started exploding and spewing magic smoke. Scared the
daylights out of me. No damage other than requiring a new PSU.
~Seth
I was just recently trying to explain this to a European friend who thought I was hallucinating this system, so I took a picture.
http://dl.dropbox.com/u/230717/temp/208YPanel.jpg
That's a picture of one of the breaker boxes in our office, showing what you described. There are 3 phases coming into the panel, each a different coil off a Y transformer, as well as a "neutral". Those are the 4 black wires you see at the bottom. You can see how the three hot phases are staggered as they go up the breaker rails.
For standard 110V service, you use a single-wide breaker and send one hot phase + neutral and you get 110V. The difference between two phases is 208 volts though, so you use a double wide breaker and can send to device without using a neutral wire. Just 2 hots and a ground. If that's all you're doing (you don't need legacy 110V service anywhere) you skip the ground wire going into the panel entirely.
-- Kevin
There are two other 3 phase setups that are somewhat common.
120/240V delta (has the third leg 'wild' at 208V to neutral, with the neutral (grounded conductor in NEC parlance) connected to a centertap on one transformer of the three required). This one has special labeling requirements and a prohibition on single-phase loads being connected to the 208V leg. This one is sometimes provided in a two-transformer 'open delta' arrangement (instead of the correct three-transformer 'closed delta') and is, you might say, 'three phase lite' in practice.
480V delta corner ground. This one is 480V three phase on three wires; one phase is grounded at the service entrance, and the other two phases are 480V to ground. This one also has special labeling requirements and no 'neutral' in the conventional sense.
Precisely the same panel layout I had in my last facility, though we didn't
use any 208V branch circuits; thanks for the pic, Kevin.
Cheers,
-- jra
I was just recently trying to explain this to a European friend who thought I was hallucinating this system, so I took a picture.
http://dl.dropbox.com/u/230717/temp/208YPanel.jpg
That's a picture of one of the breaker boxes in our office, showing what you described. There are 3 phases coming into the panel, each a different coil off a Y transformer, as well as a "neutral". Those are the 4 black wires you see at the bottom. You can see how the three hot phases are staggered as they go up the breaker rails.
For standard 110V service, you use a single-wide breaker and send one hot phase + neutral and you get 110V. The difference between two phases is 208 volts though, so you use a double wide breaker and can send to device without using a neutral wire. Just 2 hots and a ground. If that's all you're doing (you don't need legacy 110V service anywhere) you skip the ground wire going into the panel entirely.
that one looks dangerous.
In europe:
64A 240V 3-Phase input.
Out to Servers single phase, output to airconditioners with 3 phase (not at this picture).
Kind regards,
Ingo Flaschberger