Electrical Question about Data Closet.

[techyguy717]

I am not an electrician, but would like to know if my recommendation is valid.

I am recommending an additional electrical gang to be installed, (also called 2 electrical outlets) to a SEPARATE circuit.

The current limit of the existing equipment is 56 data lines. After that an additional PoE switch is needed. They want me to provide another Rack Mounted UPS to add additional electrical outlets, to support more than 56 data lines. I told them I can't recommend that, because they may flip their circuit breaker.

There is only 1 Gang currently installed in the data closet supporting about 40 PoE Phones and computers.

Total equipment in data closet is currently 2 x 32 port PoE switches, 2 x 32 port switches for other projects, 2 Internet Modems, 1 TV cable Box, 1 x 34 inch TV, 1 Wireless AP, 1 Router for computers, 2 Routers for T1 connections.

 

[DCGPX]

Well as I'm not in States cant say what size your breakers are for a circuit but I seem to recall your circuits are all radial unlike here in UK we have ring circuits.

Given that most IT equipment draws minimal current, you'd be surprised what you can put on a circuit and still not overload it.

What size cable is their single gang on, thats the deciding factor as its what determines the current it can carry.

Too many times I've seen cables 'protected' by a breaker way higher than the cable was rated for as it was ' replaced because it kept tripping'

Also you mention 'another' UPS? Is there one there already - these take quite abit of current in reality so your recommendation to err on the cautious side is valid.

Edit : One extra outlet = Yes.

Port switches - Max I'd guess at 2A each = 8A

Modems/TV Box/AP/Routers = Max 5A

TV = Max 3A

Therefore Total 16A max and thats generous

Your radial circuits are usually 20A min so well within.

I'd still say another circuit and split to priority so that IF it trips you dont lose all - Share across the UPS's

 

[techyguy717]

I'd like to clarify the 2 PoE switches provide power to 40 high quality VOIP phones, with built in video conferencing screens. They want to add a 3rd PoE switch and a 3rd UPS on the same circuit.

Each phone has only one cable, both providing data and power, from data closet.

Realistically though, we could plug in every VOIP phone to an electrical outlet at each cubical. This should save quite a few Amps from the data closet, correct? Is this a realistic alternative to installing another circuit?

 

[DCGPX]

I'd like to clarify the 2 PoE switches provide power to 40 high quality VOIP phones, with built in video conferencing screens. They want to add a 3rd PoE switch and a 3rd UPS on the same circuit.

To be honest, outgoing power part of PoE is irrelavant, its the incoming rating as this will assume full use so theoretically should be most the equipment uses under load. So if its within the breaker capacity using separate outlets at cubicles may not be necessary,

I'd look at each PoE incoming rating, add all the other equipments rated current and see what total is.

I'd still be interested in cable size and breaker size as I said before this is your deciding factor and allows an informed call over running current and risk associated .

 

[techyguy717]

The business has decided to go for another circuit. In the next 5 years, they will need it.

Is there a way to tell the cable gauge, when it is completely enclosed inside a metal tube? I understand the gauge is needed for the AMP rating? They do not have that information.

 

[DCGPX]

The business has decided to go for another circuit. In the next 5 years, they will need it.

Is there a way to tell the cable gauge, when it is completely enclosed inside a metal tube? I understand the gauge is needed for the AMP rating? They do not have that information.

Not without expensive test equipment! Visual best. That said ASSUME correctly installed use breaker as your limit minus 10% rating.

ie 20A breaker, max load should be 18A

Putting in extra outlet good move anyway as can share load. Now persuade them to prioritise what goes on each circuit and protect accordingly

 

[mr m]

Is there a way to tell the cable gauge, when it is completely enclosed inside a metal tube?

15 Amp circuit is 14 gauge wire. 20 Amp circuit is a 12 gauge wire.

Just look at the circuit breaker in the panel. It will be marked on the handle 15 or 20 etc. You can also take the faceplate off (be careful grasshopper, those screws on the side of the receptacle are LIVE, bbzzztttt) and embossed into the receptacle will be either 15A-120V or 20A-120V. If not legible or obscured by paint you can tell by looking at the wire or in your case TURN OFF the breaker, remove the receptacle, unscrew either the black or white wire and measure the gauge with one of those wire strippers with cutouts for various wires like 10,12,14 etc.

If you're not comfortable let their electrician deal with it.

 

[frederick]

If this is a business, step away from thos, and get a licensed and bonded high voltage electrician.

I use to do a lot of high voltage work back in the day, and could tell you exactly what to do, and how to do it. Still can. But here is the thing, you are not an electrician, and anything you do will violate laws because you are not licensed (or bonded if required) to perform this type of work. With a business there is a huge legal side here. If you install it wrong, if you switch out a bad breaker, you look at ot wrong, and something happens...you are liable regardless of what the customer signed, cause they can sue you to no end

When I used to do hvac, and we touched 120V, say, switching a breaker for a new one of same amperage, we needed an inspector to make sure we installed it correctly

 

[Mercenary Roadie]

I hope you're going to hire a licensed Electrician to do this outlet install.

When they show up to give an estimate, tell them what amperage you want the outlet to handle and they'll calculate the rest. There is more to it than just pulling 2 or 3 new wires in a conduit. IF you want a quad box installed with 2 duplex outlets, have them run a single 20 amp circuit to each outlet instead of a 20 amp circuit to both outlets. You'll pay a more in materials, but save a ton on labor.

In the future, all of that equipment you listed doesn't do an Electrician any good, what they want to know is what the label says on it current draw. Add all of those current draws up and it should be less than 80% of what the outlet can handle as a rule of thumb.

 

[Mercenary Roadie]

15 Amp circuit is 14 gauge wire. 20 Amp circuit is a 12 gauge wire.

Just look at the circuit breaker in the panel. It will be marked on the handle 15 or 20 etc. You can also take the faceplate off (be careful grasshopper, those screws on the side of the receptacle are LIVE, bbzzztttt) and embossed into the receptacle will be either 15A-120V or 20A-120V. If not legible or obscured by paint you can tell by looking at the wire or in your case TURN OFF the breaker, remove the receptacle, unscrew either the black or white wire and measure the gauge with one of those wire strippers with cutouts for various wires like 10,12,14 etc.

If you're not comfortable let their electrician deal with it.

That is not true, the wire size will depend on many factors and they are all spelled out in the NEC. What size wire to run for a set amperage is determined by many factors, such as conduit size, Number of current carrying wires, Temperature, Wire temperature rating and so on.

 

[mr m]

That is not true, the wire size will depend on many factors and they are all spelled out in the NEC.

98% of the time it is true but I agree with you. I've seen an electrician use 12 gauge wire on a 15 A circuit. When I asked why he said that he had that wire laying around plus on long runs hit helps alleviate voltage drop. No way can you ever use a 14 gauge wire on a 20A circuit.

The breaker doesn't lie unless some fool wired up the establishment. If it says 20A, it's 20A. The OP should just flip breakers until he finds the circuit in question.

 

[angry_geek]

It depends on what your client's needs are, what they can afford, and what they're willing to do. In my office data center, we have a dedicated 400 amp service coming in which immediately goes to commercial capacitors. The servers and ups units run on 220 volts. The entire thing is wired into a standby generator now with a 250 gallon natural gas tank. Complete overkill, but we got it on the cheap. There is also a nice Mitsubishi a.c. unit to keep everything cool if the main goes out. For 30 plus servers, my bill on that service runs $35 or so per month. With the higher voltage, everything runs cooler and more efficiently.

With a small setup, 1 or 2 servers and network equipment, I would request a dedicated 20 amp circuit run to 2 x 4-gang outlet boxes.