Got a new rack! Now questions

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greengolftee87

Limp Gawd
Joined
Oct 15, 2008
Messages
274
Ive been using a open 4 post threaded rack for some time now and more or less hated it so when I found this one I had to jump on it. However I have some questions since it came with some stuff I'm not familiar with.

The rack is a Liebert rack and UPS system.
PICS
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The white thing at the bottom is a water sensor, I can trip it with my finger but nothing happens, I'm assuming I need the UPS working first. There's also a smoke alarm in the top
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White switchy things! The top one gets serial I/O from the UPS so im not sure what it can or cant do yet until the UPS is working. The bottom one also is tied in but seems to work fine regardless. The bottom one has 6 outlets that when turned on come up 1 at a time kind of like hard drive staggered spinup, the rate is adjustable.
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Liebert UPS, not sure of its condition yet
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Looks like i could add in an additional battery back if needed. (i dont need)
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Dell rail stuff, got this with it thinking i could use it with my NORCO RPC-470, since 1 rail is attached to a very large plastic thing im assuming not? Anyone know otherwise?
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The plug on the UPS. WTF is this. It says 125v 20A. I'm assuming the big plug is since its 20A and not 15A but why is it on an angle like that. Is this bent? Since ill never pull 20A from this thing can I cut it off and replace it with a regular 3 prong plug?
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It seems like this case was custom ordered set up like this so whatever I can get working is good. Has anyone ever used a system like this? The water detector, while interesting, is pretty useless to me right now but i want to get it working anyway. Ill test the smoke alarm after work tomorrow but my #1 thing right now is to fire up the UPS and see if there's any life left in the batteries.
 
Guess I'll give a rundown of things...

Water sensor plugs into an environmental monitoring unit, not the UPS. Smoke detector may as well, but it could be independent.

Not completely certain what those white 1U things are as the pictures aren't really clear enough to get a model. From the looks of it though, the top one could be the environmental monitoring unit and the bottom a managed PDU.

The external connector on the Liebert UPS is indeed for attaching external battery packs. You can however add up to 5 though (they're daisy-chained). They also normally come with a different front bit (where the buttons and LEDs are) so it is the correct way up in the rackmount configuration (yours is currently in pedestal orientation).

Dell rails presumably aren't going to be of any use to you unfortunately. The black plastic bits are probably the cable management bits for the rear.

Yes, that is a 20A plug as you have the 2000VA model (you have a GTX2-2000RT120 if you didn't know). You CANNOT chop it off and fit a NEMA 5-15R plug. Your breakers will constantly trip if you have 15A ones and you risk fire if you have 20A ones on a 15A outlet. You may never put a 20A load on the unit, but it will draw that much irregardless of what you have attached to it when charging (even if you have nothing plugged in).
 
Blue Fox is about 90% right, except for the last part:

You can in fact replace the NEMA 5-20P (125V/20A) with a NEMA 5-15P (125V/15A) plug. It's not recommended but you can do it. The only limitation is that you can not draw the full power from the UPS as the total power from the source will be limited to 1875W (15A) vs. 2500W (20A).
The UPS will NOT draw 20A from the socket during charging as this would overload the circuit when it is charging and supplying power to the load. The charging circuits in these UPS types have a current limit. Best thing to do in your case would be to replace the NEMA 5-20P with a NEMA 5-15P, plug the UPS into a Kill-A-Watt type power meter and take a look at how much power the UPS draws during the charge cycle (you shouldn't have any loads plugged into the UPS during this test). Once you figure out how much the charger draws (I assume the batteries are drained), take 1875W (maximum power the circuit will allow you to draw) and subtract the power required for the charger which will leave you with the maximum power for your load. You should not go beyond 80% load on a circuit anyway so I would suggest you actually use 1500W instead of the 1875W for your calculation. If you follow those suggestions, you won't run the risk of tripping the 15A breaker.

You should also take out the UPS batteries and inspect them for physical damage (cracked cases, etc) and probably check the terminal voltage (SLA batteries do not take kindly to being discharged below 10.5V!!).

And you are correct, the plug you have in the picture has a bent blade, it should be sticking out straight. The Vertical blade is the HOT and the horizontal blade is the NEUTRAL. They are configured this way to prevent you from plugging this plug into a 15A socket.
 
treadstone said:
Blue Fox is about 90% right, except for the last part:

You can in fact replace the NEMA 5-20P (125V/20A) with a NEMA 5-15P (125V/15A) plug. It's not recommended but you can do it. The only limitation is that you can not draw the full power from the UPS as the total power from the source will be limited to 1875W (15A) vs. 2500W (20A).
The UPS will NOT draw 20A from the socket during charging as this would overload the circuit when it is charging and supplying power to the load. The charging circuits in these UPS types have a current limit. Best thing to do in your case would be to replace the NEMA 5-20P with a NEMA 5-15P, plug the UPS into a Kill-A-Watt type power meter and take a look at how much power the UPS draws during the charge cycle (you shouldn't have any loads plugged into the UPS during this test). Once you figure out how much the charger draws (I assume the batteries are drained), take 1875W (maximum power the circuit will allow you to draw) and subtract the power required for the charger which will leave you with the maximum power for your load. You should not go beyond 80% load on a circuit anyway so I would suggest you actually use 1500W instead of the 1875W for your calculation. If you follow those suggestions, you won't run the risk of tripping the 15A breaker.

You should also take out the UPS batteries and inspect them for physical damage (cracked cases, etc) and probably check the terminal voltage (SLA batteries do not take kindly to being discharged below 10.5V!!).

And you are correct, the plug you have in the picture has a bent blade, it should be sticking out straight. The Vertical blade is the HOT and the horizontal blade is the NEUTRAL. They are configured this way to prevent you from plugging this plug into a 15A socket.
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It can definitely draw more than its rated output when charging and certainly can go above 15A. I know mine does (I also have a GTX2). The 2000VA unit is only rated for 1400w output anyway. Swapping the plug for a 15A one would be a very poor idea as the 20A one is there for a reason.
 
I wouldn't replace the plug... It's like an appliance plug... I'd rather just get a 20amp breaker installed and have an electrician run a wire to it... That would give me the full 20amps... and I wouldn't be questioning the hack job when something goes wrong... I have seen electricians just swap out the whole cable w/the plug instead of just swapping out the plug... but Jim, I'm not an electrician... I'm a PC doctor...
 
Of course it's there for a reason (hence my comment:"It's not recommended but you can do it."). If the UPS is rated for 2000VA load, you obviously need to provide sufficient power from the source (plus the charger overhead). And of course if draws more from the circuit than what the rated output of the UPS is, hence my suggestion he should do some measurements before he uses it. But you can't pump 1875W of power into the type of batteries used in these UPS types (especially since he only has the build in batteries and no external battery packs attached). That would literally cook them to death. I assume this UPS probably uses 4 12V/7Ah batteries strung together as a 48V/7Ah source. These types of SLA batteries should be charged with an up to 2.3V per cell (float charge) or up to 2.45V per cell (fast charge) and are normally charged with a 0.1C maximum initial rate. Most battery manufacturers also specify that the initial charge current for a 12V/7Ah battery should be limited to less than about 2,2A. So this would mean that the power into the batteries should be limited to 24 cells at 2.25V = 54V (normal float voltage) * 2.2A = 118.8W

Taking losses from the charging circuit into consideration (chargers efficiency) as well as the power required by the control circuitry, your UPS should probably draw around 150W maximum when charging fully discharged batteries and no load attached.

Every UPS is different and the example I gave above is based on a UPS that uses 4 12V/7Ah batteries. UPS systems with larger batteries would have higher charging currents and hence will draw more power from the circuit, but they will NEVER draw as much power to overload a circuit when only charging the batteries an no load is attached even when you hook up a 2000VA UPS to a 15A circuit!

It's ok to hook up a 20A UPS to a 15A circuit (keeping in mind that you can't draw the full power from the UPS or the circuit), but you should NEVER plug a 15A unit into a 20A circuit as this could result in a fire!

@Bookmage: Personally I would do the same, but for some installations, that's not possible or not feasible and I doubt that the OPs power draw requirements are high enough to justify the cost involved in running a new 20A circuit!
 
How do you figure that if you plug a 15 amp ups into a 20 amp circuit is a problem? That makes absolutely no sense. If the circuit is rated at 20 amps then it's a 20 amp circuit it doesn't matter if you plug in a 5 10 or 15 amp load
 
If the circuit you're plugging into is already a proper 20 amp circuit (20 amp breaker, 12ga wire) just get the outlet replaced with a 20 amp outlet. It's cheap and easy to do.

It's far better than the 15 amp plug you stick on melting if you are in fact drawing more than 15 amps on a consistent basis.
 
@Angus: A circuit is fused for it's maximum capacity, which means that if you have a 20A circuit breaker, your cabling would be sized accordingly (12AWG for 20A). If you use an appliance that is designed for a 15A circuit, the cable attached to it (and the internal wiring) is designed for a circuit capacity of 15A, which means that if there was a fault in the appliance, the cable and wires are sized to trip a 15A breaker. If you connect the appliance to a 20A circuit, the cable/wiring may not be sufficient to trip the breaker and could cause a fire due to overheating as it would be the weakest link in the chain!
On the other hand, an appliance that is designed for a 20A circuit can run on a 15A circuit (if the total power draw is less than or equal to the 15A feed). Since the cable or internal wiring is 12AWG and can handle up to 20A, if the appliance does have a fault, it would easily trip the 15A circuit breaker without overheating and potentially causing a fire!
It's always better to oversize the wiring to reduce losses and run into potential issues. It's dangerous and against code to put a 20A breaker on 14AWG wiring.

@valve1138: I doubt the OP either has a 20A circuit where he plans on putting the rack nor would he have 12AWG wiring if the outlet has a 15A receptacle! Residential dwellings are not normally wired for 20A except in certain circumstances that require it. The norm is 14AWG (15A branch circuit service).
The only exception to this is that you might find 12AWG in really long branch circuit runs. Also in commercial and industrial buildings/installations you can find that they use 12AWG wiring for all the 15A circuits.
 
@valve1138: I doubt the OP either has a 20A circuit where he plans on putting the rack nor would he have 12AWG wiring if the outlet has a 15A receptacle! Residential dwellings are not normally wired for 20A except in certain circumstances that require it. The norm is 14AWG (15A branch circuit service).
The only exception to this is that you might find 12AWG in really long branch circuit runs. Also in commercial and industrial buildings/installations you can find that they use 12AWG wiring for all the 15A circuits.
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You may very well have 20 amp circuits, with 12 ga wire, and 15 amp duplex outlets on a circuit. It's quite common and perfectly fine under code.

You're making far to many assumptions.
 
@valve1138:I made my assumption the the OP doesn't have a 20A outlet based on the fact that he did not know what kind of plug this was and hence posted a picture of it... I could be wrong ... :)

And you are correct, you can have duplex 15A as well as 20A outlets on a 20A breaker.
 
Wow. Thanks for all the replies.
Yes Blue Fox, the top one seems to be environmental and the bottom one is power distribution. I tripped the water sensor for a minute but got nothing but who cares

For now I'm just not using the UPS and am using my previous CyberPower 1500VA UPS. I'll deal with it when I move in a few months, for now its a theft deterrent cause it makes the rack 50 lbs heavier haha.

Ill be getting some acrylic in the next few days to make a front door insert and then I think ill be done.

Here's a current pic, and yeah, my desk's a mess.
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Top to Bottom:
Environmental unit
PDU
Receiver
Cisco 2500 series router( AKA Shelf)
Server
Pfsense laptop
Netgear 16 port gig switch
unused liebery UPS
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@treadstone sorry but no, curcit breakers are in place primarily to protect the wire in the walls and the rest of the system. afci/gfci have additional protection to assist the end user/equipment from shock/fire. the purpose of curcit breakers is to keep you from mealting your wires in the walls and buring the house down. most ups's come with built in curcit breakers to protect them selves from over usage. 20A is the maximum you can run throgh the wire @ the pannel to all devices plugged in. 15A device in a higher rated curcit is normal other wise you couldent plug in your alarm clock to the same plugin your pc goes. I can cite the nec codebook if need be.

@greengolftee87 nice score... Dont cut the cord and fit to a lower. i had to re plug mine due to it having twistlocks instead of the end you have. thats the only reason you should change ends. doing otherwise is just asking for problems. Im getting ready to run a pair of 30A runs for my av and computer equipment. I may even go back to the twistlock connectors so no one can mistakenly use them. they will both be in the same breaker housing and on the apliance side of the 110 so that the surge protectors and ups's wont affect automation traffic as much. im rewireing my pannel to put the lights and the non appliance outlets on the other side of the 110 so signal strenght will be better.

hehe wish i could run off with that lebiart... gota spend about 300-400$ to replace batterys in the units i have.
 
Yeah i paid just over 200 for the rack, UPS, pedestal, and the dell rails. The guy actually had quite a few left. But for now the UPS isnt being used. When the weather warms up Ill hit up my parents house because they used to have a pool and the electrical for the pump had to be on its own breaker and was a twist lock. Ill see if its a comparable circuit. I just want to try it somewhere to see if the batts are any good
 
im in the process of moving all my equipment over to racks the stations around the house wont be but the several systems I use daily including my desktop will. found some old 2u server cases im going to hack up so I can put the systems in to :)

just fyi the twistlock usually are for 30A circuts and many pumps are 220v instead of 110. the 220 twistlocks have 4 prongs.
 
phalantice said:
im in the process of moving all my equipment over to racks the stations around the house wont be but the several systems I use daily including my desktop will. found some old 2u server cases im going to hack up so I can put the systems in to :)

just fyi the twistlock usually are for 30A circuts and many pumps are 220v instead of 110. the 220 twistlocks have 4 prongs.
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yeah im pretty sure ours was a 3. Ill take a better look in a few weeks when it warms up
 
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