32A to 2x 16A

DrySand · 22 Jul 2020

I am currently looking at installing some equipment in a small IT comms room and am looking for some advice on the current setup and how to proceed, I am not an electrician myself.

1: Currently there is a 32A supply being fed directly into PDU with 13A sockets, same as the the link below, my first thought is that this is unsafe, but as each plug would be fused am I wrong? https://cpc.farnell.com/lms-data/pdu-12ws-v-32cmdo/12-way-vert-13a-sw-pdu-32a-plug/dp/EN84502

2: I would prefer to introduce two UPSes for redundancy as per standard practice. The UPSes are 16A devices, I believe that these shouldn't be plugged directly into the 32A supply and that a splitter with 16A protection should be used as per the below, is that correct?
https://www.dcdi.co.uk/shop/05m-32-amp-comm-plug-to-2x-16a-comm-skt-mcbs

JohnD · 22 Jul 2020

is this in your house?

Or in a place of employment?

Why aren't you using an electrician?

If you are in the UK, why doesn't your circuit have 13A sockets on it... which seem to be what you're using for your equipment?

is it in an industrial unit, or portacabin?

What circuit supplies the air conditioning?

is your equipment in LAN cabinets? Racks?

What is the total ACTUAL load of your equipment, in Amps?

How do you know the USPs need 16A?

DrySand · 22 Jul 2020

These are the UPS that we usually buy, which are rated at 16A:
https://www.apc.com/shop/uk/en/products/APC-Smart-UPS-2200VA-LCD-RM-2U-230V/P-SMT2200RMI2U

The draw when powering up all the equipment will be about 5000W / 21A split between the two UPSes.

At normal running the current will be ~11A split between the two.

The installation is in an office building.

JohnD · 22 Jul 2020

more questions, please see above.

I think you would be unwise to specify it as an amateur.

You might like to become aware of the Electricity at Work Regulations

https://www.legislation.gov.uk/uksi/1989/635/contents/made

oldbutnotdead · 22 Jul 2020

Why 2 x UPS. Unless you've got some monsters, there'll be enough runtime on them for an orderly shutdown in case of power fail (last ones i specced were set to run as normal for 15 minutes, if outage was longer then tidy up open files, dismount volumes & down the servers).
What's running off that posh strip at the moment- is it all going to run through the UPS?
That 12 way block is fine, cable size is appropriate for the supply, load cables are protected by fuses in plugs.
Your 32- 2 x 16 splitter is fine.
No electrician required so far. What outputs do the UPS' have? What loads are you running?

DrySand · 22 Jul 2020

oldbutnotdead said:
Why 2 x UPS. Unless you've got some monsters, there'll be enough runtime on them for an orderly shutdown in case of power fail (last ones i specced were set to run as normal for 15 minutes, if outage was longer then tidy up open files, dismount volumes & down the servers).
What's running off that posh strip at the moment- is it all going to run through the UPS?
That 12 way block is fine, cable size is appropriate for the supply, load cables are protected by fuses in plugs.
Your 32- 2 x 16 splitter is fine.
No electrician required so far. What outputs do the UPS' have? What loads are you running?

I've edited my earlier reply to include some additional info.

Each item of equipment (Few servers, few switches) has 2x power supply. One supply from each is plugged into each UPS, that way the equipment stays up if one UPS fails.

JohnD · 22 Jul 2020

I just read the spec and I didn't see that it says it needs 16A

Where should I be looking?

I did see where it says "
Input Connections
British BS1363A, IEC-320 C20, Schuko CEE 7/EU1-16P"

presumably it means "one of the following..."

DrySand · 22 Jul 2020

JohnD said:
I just read the spec and I didn't see that it says it needs 16A

Where should I be looking?

I did see where it says "
Input Connections
British BS1363A, IEC-320 C20, Schuko CEE 7/EU1-16P"

presumably it means "one of the following..."

This is what the back of the unit looks like, 16A is specified there:
https://cdn-reichelt.de/bilder/web/xxl_ws/E910/APCSMT2200RMI2UC_03.png

JohnD · 22 Jul 2020

it should be in the spec. The spec seems to say output is 1980W

I believe the IEC connector shown has a maximum rating of 16A.

On your pic of the back, it says "see top cover for....power rating information"

What does it say on the top cover?

DrySand · 22 Jul 2020

JohnD said:
it should be in the spec. The spec seems to say output is 1980W

On your pic of the back, it says "see top cover for....power rating information"

What does it say on the top cover?

It says:
1.98kWatts / 2.2kVA

JohnD · 22 Jul 2020

DrySand said:
It says:
1.98kWatts / 2.2kVA

Uh-huh.

Does it say "input rating" or "output rating?"

oldbutnotdead · 22 Jul 2020

You could run those from the 13a sockets on the 12 way powerblock- one of the supply options is BS1363A.
You still have a single point of failure either way the 32a supply.
13a fuses are more tolerant of very short high-current events, depends how much you want to protect the front end of the UPS.
You're not going to get much runtime off them- apc's site is poorly at the mo on my phone but it reckoned 5 minutes at 1980w load- used to take that long to drop 20 gig Netware file & print, can't believe app or ecommerce servers will be any quicker.
EDIT Better- 9 mins at 1400w, still not a lot. Up to you but best check how long your servers take to shut down nicely. No electrical issues, though you may be introducing an additional fault path. Currently if 1 device plugged into that 12 way (with a 3a or even 1a fuse in the plug) fails short-circuit, the plug fuse should blow before the 32a supply mcb.
It would appear that there's no individual fusing on the ups outputs so a fail to short circuit of 1 device will kill all devices connected to that ups.

bernardgreen · 23 Jul 2020

DrySand said:
These are the UPS that we usually buy, which are rated at 16A:
https://www.apc.com/shop/uk/en/products/APC-Smart-UPS-2200VA-LCD-RM-2U-230V/P-SMT2200RMI2U

which according to the web page are Not available in United Kingdom

DrySand said:
I am currently looking at installing some equipment in a small IT comms room and am looking for some advice on the current setup and how to proceed, I am not an electrician myself.

Employ a competent electrician with experience in designing and installing power supplies to IT comms equipment,

ericmark · 23 Jul 2020

Even for electricians setting up an UPS is not easy, the simple way is a UPS for each item, as with a bathroom shaver supply if the earth is lost when running on battery power there is no real problem when powering one item, as soon as two items use the same UPS then you need to ensure all the required bonding and earthing together with RCD protection is valid when on battery power, remember any RCD on the supply to the UPS will do nothing to protect you from UPS output once on battery power.

I looked at fitting a large UPS for whole of office, however it was more expensive than single UPS, and it was complicated to wire complying with British regulations. In the main what you show is used to power servers, normally in a locked air conditioned room, where only competent persons are allowed access, this is very different to a normal office health and safety wise, often it needs pre isolation of the fire fighting equipment before entry.

This is not a DIY job, and asking on a DIY forum how to install is not the correct method. And from your questions you don't seem to have the skill required to do this job.

SimonH2 · 25 Jul 2020

DrySand said:
These are the UPS that we usually buy, which are rated at 16A:
https://www.apc.com/shop/uk/en/products/APC-Smart-UPS-2200VA-LCD-RM-2U-230V/P-SMT2200RMI2U

The draw when powering up all the equipment will be about 5000W / 21A split between the two UPSes.

At normal running the current will be ~11A split between the two.

Time to go back to the drawing board. 11A is 2640VA. If one UPS trips/fails then the other one will immediately go into overload - and if the power is off, drop your loads.
For powering up, your 5kW will also put both UPSs into overload.

For a dual redundant setup like you are trying to build, then you need each UPS to be capable of running the entire load on its own - with some headroom. The APC units are "OK", and I've installed a few if the 2200 RM units (amongst others) over the years.

Whatever you install, adding additional batteries massively increases runtime. The last 2200 I installed, we added an extra battery cab - 3x the battery, around 5x the runtime. It's a basic fact of lead acid batteries that the faster you discharge then, the lower their useful capacity.
Also, assume you'll need new batteries around every 3 years - less if you don't keep them cool or if you work them hard (as in doing discharge tests or riding out power cuts).
Until you get to the bigger units, they don't have the ability the monitor individual battery strings. If a cell fails, it'll happily cook that string.

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32A to 2x 16A

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