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Businesses Hardware

Testing Electrical Capacity of New Offices? 71

Posted by Cliff from the tossing-on-a-load dept.
An anonymous reader asks: "Running a small graphic design studio, we've hit a snag that I'm sure many tech-reliant small businesses have hit before: our small flock of file servers, multi-processor machines and 22" monitors draws more electricity then the wiring in our current space can take. We're looking for a new space for this and other reasons, and as we look around we're generally forced to take the word of landlords as to what sort of amperage an electrical system can provide. Does anyone in the Slashdot community know a reliable way to test and see if an electrical system can support the needs of a computer-reliant business?"
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Testing Electrical Capacity of New Offices? More

Testing Electrical Capacity of New Offices?

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  • Have you considered? (Score:5, Insightful)

    by krangomatik ( 535373 ) * <[moc.oohay] [ta] [awakijufr]> on Wednesday March 10, 2004 @04:10PM (#8524284)
    Bringing a qualified electrician along when looking for new office space. Or at least having an electrician give it a looking over before you sign a lease. They should be able to look at the power coming into the building as well as the current distribution system within the building and give you some idea as to whether or not it could meet your needs.

    Total available amperage to your offices doesn't always do you a whole lot of good if you can't get the circuits you need to your server rooms. Be sure to discuss with the landlord any plans you may have to add or move existing circuits around.

  • Check the breaker box (Score:5, Informative)

    by jspey ( 183976 ) on Wednesday March 10, 2004 @04:19PM (#8524398)
    Ask to see the breaker box that holds the breakers to your office space. The amperage that will trip each breaker should be printed on it. If it's not clear which breakers go to your office space (perhaps because there's one big box for the building and it's not labeled well, or there are different boxes for each office and they're not labelled well, either), ask the landlord.

    Put in the lease that the electrical system in they office space will have a capacity of X. Have a clause that says that if this isn't the case, the landlord will spend his own money to fix it in X weeks/months/etc, and if he doesn't then you get free rent until he does, as well as the option to break your lease without penalty. Be willing to pay an electrician to check that the max amperage of the space is what it's agreed to before you sign the lease, though. Also make sure the lease allows you to have an electrician come in and do said checking.

    If you're really worried, put a significant penalty into the lease if the amperage is too low (I'm sure you don't want to move any more than you have to). You will probably have to pay a little extra for this. If your landlord balks at this, tell him to get an electrician who will back his work do the inspection, so that the electrician pays the penalty and the landlord doesn't.

    • Re:Check the breaker box (Score:4, Informative)

      by V. Mole ( 9567 ) on Wednesday March 10, 2004 @04:23PM (#8524469) Homepage

      The amperage that will trip each breaker should be printed on it.

      And then divide that number by two. Or 1.5, maybe. Anyway, you can't pull 30A (or even 29A) through a 30A breaker, not for very long.

      • Re:Check the breaker box (Score:1, Insightful)

        by Anonymous Coward
        A good rule of thumb is 70% of rated capacity here. For 30 amp breakers, assume that 21-22 amps is fine forever. Above that, *plan* to call an electrician to add another leg off of the transformer. *Budget* time and money for this.

    • Re:Check the breaker box = bad assumption (Score:4, Informative)

      by managerialslime ( 739286 ) on Wednesday March 10, 2004 @04:55PM (#8524826) Homepage Journal
      ?????????????
      >>Ask to see the breaker box that holds the breakers to your office space. The amperage that will trip each breaker should be printed on it.
      ?????????????

      Really?

      If the last electrician "installed" extra breakers in anticipation of future needs, (i.e. you've got switches without connecting wires,) looking at the box won't do you any good.

      This is another reason why you should have a licensed electrician test the required electrical capacity prior to signing a lease.

      The last two facilities I was involved with had to be upgraded. The first, because when we installed UPS' the heat from the UPS' overwhelmed the air conditioning.

      The second because when an open space was suddenly converted to cube space, employees brought in a boatload of space heaters and pop-goes-the-breakers.

      With regard to landlords putting guarantees in the lease, good luck. Many will tell you it's between you and the local utility and the most they will do is provide their "best efforts."

      What you can OFTEN do is have your licensed electrician kill two birds by scheduling a representative from your local utility to meet with him when he inspects the site. At that time, any problems with the local power distribution grid THAT THE LANDLORD MAY NOT KNOW ABOUT can be identified.

      With regard to estimating your needs, a google searches that include btu, kwh, "load estimation", etc. provides lots of links to help you develop a spreadsheet of what you need.

      • Re:Check the breaker box = bad assumption (Score:1, Informative)

        by Anonymous Coward
        This is very good advice, but I would add a third party -- the HVAC people, and if you have chilled water that is maintained by another party, have them show up as well. That is a very good idea. And come to the meeting knowing how much the current draw is for each of your machines + 20%.

        On another topic, the air filters that most HVAC companies and folks use are really, really crappy. It is worth the extra money to budget to get good air filters (we use 3M Filtrete air filters in our building and we no

    • Re:Check the breaker box (Score:5, Informative)

      by MarkedMan ( 523274 ) on Wednesday March 10, 2004 @05:03PM (#8524939)
      Whoa. While checking the box is the right way to go , simply adding up the current available on individual breakers is absoltely NOT! What you need to know is what kind of service the building has. If your space has its own service, then that is what you get, 200 Amps, 500 Amps, 1000 Amps. That is the total you can draw at once.

      You still are not homefree though. State electrical codes limit how much each run can draw, say 20 amps. Even if you have a 10,000 Amp service, you can't draw more than 20 amps on that line. Note that the line can, and probably does, have mulitple outlets on it.

      This is why you need a professional electrician. But you have to arm him with some prior information: In this room I want to have X pieces of equipment plugged in. Piece 1 draws 3 Amps, Piece 2 draws 1 amp, etc.

      You can find out how much each piece draws with a clamp type ammeter, or rather your electrician can. Note that it is not unusual for equipment to draw significantly more at system startup.

      The electrician can then calculate how many outlets and how many pieces you can plug in.

      A suggestion: Color code and number the outlets for sensitive equipment and keelhaul anyone who plugs in a hair dryer or microwave. In fact, banish microwaves to some far off dungeon, as they emit noise at exactly WiFi frequencies (both use the unregulated spectrum, because, well, it is unregulated.)

      Finally, I would also suggest putting all your sensitive stuff on an isolating power conditioner. This is NOT a battery backup, you can add one of those before or after it.
      • a old medical office can have suprisingly electrical capacity, an X-RAY unit can put out 50mA at 145KVpeaks which works out to 7250W, at 230V thats 31 amps so it's probably on a 45 Amp circuit by it's self to allow to peak surge. An added advantage is you can have a server room with lead lined walls!

  • Easy. (Score:5, Funny)

    by pi_rules ( 123171 ) * on Wednesday March 10, 2004 @04:20PM (#8524417)
    Have everybody bring in their microwave when touring offices. When they say it'll support situation X have people walk out their car, grab microwave, and plug it in. See if they're still confident in supporting that load. If they are, flip 'em on.

    Nothing beats proof you can actually see. Just figure out what how many microwaves you need to simulate your load.
    • Iron's draw a ton of current (I know they used to draw about 1000W) and it seems a bit easier to bring in 5 irons than 5 1000 W microwaves. Ofcourse Iron's will only draw the current for a few minutes (till they get hot), so you might want a fan or some water to keep the temp below the turnoff point. It's probably easier to bring in an electrician who can tell you if the space supports your electrical needs.
      • Leave them running for 2 days and see if the air conditioning system can keep up. :)

        If the office includes backup power, make sure the air conditioners are part of the protected load. If commercial power fails and the generator kicks on, your server room will keep running but get very hot, very fast without proper cooling.

  • landlord scum (Score:1, Informative)

    by Anonymous Coward
    most building unless they were build 50+ years ago should be fine. make sure your server room has a couple dedicated circuts so if you blow a fuse the whole thing wont go out. it all depends on what you have. 3 servers in a closet and 10+ machines in a 1000sq ft building with at least 6 dedicated circuts will be fine. if you are paranoid about it bring an electrician show him what you have and what type of building you are moving into.

  • Dummy loads (Score:3, Insightful)

    by Spamalamadingdong ( 323207 ) on Wednesday March 10, 2004 @04:24PM (#8524484) Homepage Journal
    One way is to bring things which can pull as many watts (and preferably volt-amperes as well as watts - remember, computer gear does not have a unity power factor [look it up]) as your server stuff and plug it all in. Add a safety factor, say 20%; plug your dummy load in, turn it on, see if circuits stand up.

    One good dummy load would be a bag full of travel-size hair dryers. They pull roughly 1500-1700 W apiece, and they don't take much room. You could plug a whole bunch of them in and see if you lose breakers; if you have 5 KW of server demand I'd go for about 7 KW of dummy loads for testing.

    Note that this is over and above checking the ampere ratings on the breakers for the circuits in question. You don't necessarily know what's upstream, but like any other part of your production system you want to stress-test it before you rely on it.

    • Re:Dummy loads (Score:3, Funny)

      by karnal ( 22275 )
      Plus, if you're using a bunch of hair dryers, you can also test the air handling system to see if it will keep up with the heat disbursement at the same time!
      • Unless your dummy load store energy somewhere else (for instance chemical, by electrolysis of water, or mechanical, by filling compressed air tanks, or pumping water higher etc) all of it goes to heat. Almost all household and computer applicances are like this - the heat dissipation is equal to the draw. Computers, heaters, TVs, DVDs, playstations, light bulbs.

        It's even true of stuff like your refrigerator, or the pump on your fishtank - but in those cases you have to average over time at steady state f
      • Plus, if you're using a bunch of hair dryers, you can also test the air handling system to see if it will keep up with the heat disbursement at the same time!

        ... and you could offer complementary wash-and-dries to your staff!!

  • Circuit breakers are labled by how much current they'll handle before they blow. Find out which circuit(s) are for your office and just take a look.

    --Chris
    • just rememember that you ahve to take 80% of the ciricut ratings for max load. so a 20 amp can have 16 amps on it, a 15 can have 12.

      having an electrician along, who knows what you have, and how easy it will be to add circuts later to the new place.

  • 22" Monitors? (Score:2, Interesting)

    by vasqzr ( 619165 )

    I'd assume you're using CRT screens.

    LCD's to the rescue!

    A good 21" CRT is going to suck down 110watts+, an LCD will probably do 30...

    Plus, If each of them are 4 square feet, thats 88 sq feet less office space, or one more cube.

    • Re:22" Monitors? (Score:4, Informative)

      by Graelin ( 309958 ) on Wednesday March 10, 2004 @04:37PM (#8524630)
      The poster specified that they are a graphics design studio. Chances are they're using high-end CRTs for the color quality / contrast ratio.

      Most LCDs are lacking in this area and those that are not cost significantly more than a similarly capable CRT.
      • I'm betting on Apple Cinema Displays. They have quite good color calibration as far as LCD's go.

        You'ld be surprised at the number of graphics professionals that use LCD's, even with the known quality and contrast issues.

        - BBK
        • Good color calibration...realtively, realistic contrast. no.

          What you see and what you get is consitently further apart on the Cinema Display than in comparison to a Barco CRT. Now granted you are spending the same amount of money on the Barco as you are on a Cinema Display, but you then get the ability to control your focus and color across a 9x9 grid of the screen. Oh and a reliable controlable and calibrated monitor that can be viewed from any angle...a must when working with clients in shop.

  • Like others have said.. A qualified inspection will be best, just as if you were buying a home.

  • Airflow (Score:2, Informative)

    by Kobal ( 597997 )
    You may also want to check how easy it will be to keep the rooms cool without adding too many electrical systems. If the airflow in the building isn't sufficient, you'll be drawing much more juice in summer.
    Of course, depending on where you are, you may have the same issue in winter with isolation and portable heaters. If you use AMDs, this won't factor as an *extra* load, though.

    • Hot stuff (Score:4, Funny)

      by fm6 ( 162816 ) on Wednesday March 10, 2004 @05:35PM (#8525327) Homepage Journal
      I'm reminded of a bit of tech history [ibphoenix.com]:
      After a few winter months, the gas company sent us an estimated bill for $350. Our bills had been between one and two dollars because we heated the space with computers rather than gas. Mass Gas was convinced we were stealing from them. They replaced the meter twice, and still got absurdly low readings. Eventually the meter reader came up to our office agreed that the computers produced a lot of heat
      • Actually, that really is another thing to consider. When you're selecting a server room, you want not only good dependable power, but proper airflow and ventilation. I have a backroom with only a few servers, a bunch of switches, and other networking+A/V equipment. For awhile in the winter it got quite cold, I moved out of my normal office area and hooked my laptop up off one of the switches directly: nice and cozy.

        In the summer though, that room is a bit warm. I could definately see how a company with se
  • Do not take the landlord's word for anything. In your lease add language that you can cancel the lease in writing up to two week after it was signed if you determine the facility does not have XXX sustainable amps of electric service.
  • check your actual amp usage using an amp gauge. this will eliminate the guesswork and math involved. what you want to do is turn on your maximum load, check your circuits using your amp gauge and see whether or not your circuits/fuses can support that load.

    the other thing you have to remember is, each individual circuit might be able to support the load fine, but your load might be higher than the rating for your riser cable. if you have 10AMPs going on 10 circuits but your riser is only rated for 60AMPs,

  • Really simple test (Score:1, Funny)

    by Anonymous Coward
    Take all your computer equipment with you to the office you're thinking of renting. Plug it all in, and leave it for an hour or so. If the building burns down, that's a bad sign -- find another site. Otherwise you should be ok.

  • Test (Score:3, Funny)

    by BCoates ( 512464 ) on Wednesday March 10, 2004 @05:01PM (#8524907)
    Go buy a handful of These [digikey.com]. Each one in parallel should draw ~1.0-1.3 Amps across a power jack, and scare the living crap out of whoever's showing you the office.

    Or if you're feeling cheap, use These [digikey.com] but don't leave them powered for more than 5 seconds. (read the datasheet).
    • LOL

      Heaters or hair dryers are much cheaper per watt, plus no worries about how to plug them or safety.

      Once when testing a power supply I was building I just used unspooled wire in water. If it was on the spool it would have started smoking in no time but this way it just heated the water. The power supply did 35 V DC. Now try that with 120 VAC; that should be even more scary!

  • Need to talk to your realtor. (Score:4, Informative)

    by R2.0 ( 532027 ) on Wednesday March 10, 2004 @05:03PM (#8524928)
    If you are moving into a new space, you should have a construction allowance built into the lease. This will cover reconfiguring the office space and changing the electrical & mechanical systems. Why worry about mechanical systems? Because if you are going to need an electrical upgrade due to increased power consumption, you will need upgraded HVAC.

    Before the lease is signed, get a design done and get bids on the work. The bids will give an honest account of the suitability of the space. You can now back out or go forward. If you go forward, negotiate the lease terms and the maximum cost of construction.

    The work gets the work done by contractors, bills get paid by the landlord, you pay for it in your lease and it comes under operating expenses instead of capital expenditures - your accountant will love you (after they curse you for the up front hassle)
  • Hire an electrician who has a Circuit Breaker Tester for a few hours. Plug the tester in an outlet, and it trips the breaker and measures how much current it took to trip the breaker. Then see how many other outlets lost power. Repeat until you either are sure you have enough power or all the outlets have been accounted for.

  • bring in supplemental power (Score:4, Funny)

    by Anonymous Coward on Wednesday March 10, 2004 @05:26PM (#8525233)
    Oh, this is easy to fix. We had the same problem at a small 4-story office rental.

    You need to bring in power from an outside source. Due to electrical codes, and the questionable ability of your existing wiring, I recommend the following procedure.

    First, you need to rent some space in an adjacent property. Preferably at the same height from the street as your current property.

    Then you need to buy 10-20 large microwave ovens, approx. 50 feet of copper tubing (like you can get at the hardware store), a set of wrenches and screwdrives, and 10-20 metal (not plastic) trash can lids.

    Unfortunately I can't go into more details due to the gag order but I think you can figure it out.

    Our power problems are solved. However we had to give up WiFi. On the plus side, our coffee is always hot!

    Hope this helps.

  • Use a Multimeter (Score:2, Informative)

    by max born ( 739948 )
    You need a heavy duty multimeter. You can get one with a rating of about 20 amps AC for under $50. like this [digital-meters.com] for example.

    Hook the multimeter up with a variable resistor (also rated for 20 Amps) in series with the circuit you want to measure.

    (+)-->resistor-->multimeter-->(-)

    Open up the resistor (slowly) until the circuit breaker or the fuse goes. Note the amps that this happened at. That's your max.

  • Low power computers are becoming available. Do you really need P4s/Athalons, or can some VIA/Transmeta systems do the same job? Do you really need hard drives everywhere, or can you boot from tiny Flash disks, and only have one big RAID system in the server room? Do you really need desktop computers, or can laptops work better for everyone while drawing less power[1]?

    You save several ways, if the above works. First your utility bills go down. Second, environmental impact goes down. Third, you can b

  • I've already started buying low power equipment just to drop the heat generation to give our aircon a fighting chance. I'm sure you'll have heaps of reasons why you've got to have exactly the equipment you've got, but have a really good think about how you might reduce power requirements and you'll probably find something that won't adversely affect your business as much as, say, moving.
  • In the UK, the supplier owns the service fuse and the meter, the customer owns everything connected to the other side of the meter. The max current you can draw is the rating of the service fuse (typically 100A). Large buildings have a 3 phase supply which means you can spread the load across the 3 phases (so you get 300A)
  • Go to the town hall, or whatever they have. Ask to see if any electrical plans were filed for the building. If not, it's probably a small building, and you could probably just ask to go down to the basement and look at the breakers yourself. Yes, it's true, the breakers might provide more juice than the wiring can handle, but you do have insurance, right?

  • use ohms law (Score:2, Informative)

    by splungent ( 629257 )
    Use ohms law to figure out power consumption. e=i*r volts = amps * ohms or p=e*i Power(in watts) = volts * amps Oh..... Just go here: http://www.grc.nasa.gov/WWW/K-12/Sample_Projects/O hms_Law/ohmslaw.html or here: http://www.knovel.com/knovel2/Toc.jsp?BookID=687
  • The answer is simple go out and buy 30 space heaters. Buy the size that will fit under your typical secretary's desk. "Why," you ask? Well the answer is quite simple actually. That's exactly what will happen in your office once cold weather sets in. I can no longer count on one hand the number of times I've seen this happen (all within one company!). A secretary or receptionist gets cold and brings in a small 1000w space heater and plugs it in under her desk. More often than not she simply plugs it i

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