Michael Brown michael at supermathie.net
Sat Aug 17 02:33:41 UTC 2013

```On 13-08-16 05:47 PM, Nick Khamis wrote:
> We are in the market for a APC UPS, and had a few questions. We are not
> that familiar with APC, and was hoping for some clarity. Our power demands
> will be for a unit that will sustain 3 kW/4 kVA scalable to 8 kVA.
The model you're looking at looks good for your needs. The electrical
spec sheet seems WAY more readable than the webpage by the way:
http://www.apcmedia.com/salestools/ASTE-6Z8LSA/ASTE-6Z8LSA_R0_EN.pdf

The reason you're looking at the input voltage on the webpage and
getting confused is probably:
"Input voltage range for main operations: 96 - 138V (Line to Neutral)"

What that REALLY means is that it will function as long as the incoming
line voltage is in the 122±16V bracket (i.e. the UPS can tolerate under
and over-voltages). That's hot-to-neutral voltage.

Now, in Canada when you're running on 208V you're USUALLY getting two
hot phases at 120° phase offset (each at 120V hot-to-neutral) giving you
a RMS voltage (think of it as the time-based mean voltage) of 208V, not
the 240V hot-to-neutral you may used to... elsewhere. Sometimes you'll
get two hot lines of 120V at 180° phase offset, giving you 240V. In rare
cases you'll actually get 240V hot-to-neutral.

This UPS will be happy with either (it says on the spec sheet: Input
voltage: 200, 208,  or 240).

As for the output, first a quick primer on reading the NEMA plug types:

*\$LOCK\$VOLTAGE-\$AMPERAGE\$END*
LOCK = L | "" (if L, it means twist lock end)
VOLTAGE = 5 | 6 | 14 (5?120V, 6?208 or 240V, 14?120/240V combo i.e. 2
hots, neutral and ground)
AMPERAGE = 15 | 20 | 30 (literally 15A / 20A / 30A)
END = P | R (Plug or Receptacle)

So you'll want to plug your 120V PDU into the L5-20R receptacle and
you'll need a cable with a L5-20P at one end an a C13 or C19 (depending
on what your PDU takes as input) on the other. Such as:
http://ca.startech.com/Cables/Computer-Power/External/8ft-IEC320-C-19-to-NEMA-L5-20P-123C-Power-Cord~PXTL520C198

(btw, do note that those two L5-20R outlets only give you 4800VA × 0.8
of total power. You'll need to hardwire or use the L14 receptacles as well)

As far as STONITH goes, the only control you'll have is all ports off or
all ports on. You'll want a PDU with switched outlets if you need more
granular control.

(plug time: if you want more help speccing this out and a quote, feel
free to email me at netdirect.ca as we can sell this).

M.

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