Testing Electrical Capacity of New Offices? 71
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?"
Have you considered? (Score:5, Insightful)
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.
Re:Have you considered? (Score:3, Informative)
Look at JWZ's experiences at the DNA Lounge with electricity for some pointers and stories:
For one:
http://www.dnalounge.com/backstage/log/2000
here's a tiny url to a google search for all the related DNA stuff http://tinyurl.com/2msyt
Re:Have you considered? (Score:2, Funny)
Mostly revolving around the fact that they would not be able to run off of a generator easily...if at all.
"because there are other people here to freak out for me, if freaking is warranted. They'll handle it."
One of the people he has to "handle it" woke me up from a well deserved nap to ask where one can get a generator at 9pm on a Friday...answer: you can't.
I am a karma whore! And how! (Score:2)
http://tinyurl.com/2msyt [tinyurl.com]
Re:Have you considered? (Score:2, Funny)
Re:Have you considered? (Score:2)
Check the breaker box (Score:5, Informative)
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)
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)
Re:Check the breaker box = bad assumption (Score:4, Informative)
>>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)
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)
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.
Re:Check the breaker box (Score:3, Interesting)
Easy. (Score:5, Funny)
Nothing beats proof you can actually see. Just figure out what how many microwaves you need to simulate your load.
Re:Easy. (Score:1)
Re:Easy. (Score:2)
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)
Dummy loads (Score:3, Insightful)
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)
Load = heat disbursement (Score:2)
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
Re:Dummy loads (Score:2)
Ask to inspect the fuse box? (Score:2)
--Chris
Re:Ask to inspect the fuse box? (Score:1)
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)
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)
Most LCDs are lacking in this area and those that are not cost significantly more than a similarly capable CRT.
Re:22" Monitors? (Score:2)
You'ld be surprised at the number of graphics professionals that use LCD's, even with the known quality and contrast issues.
- BBK
Re:22" Monitors? (Score:1)
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.
Qualified inspection (Score:2)
Airflow (Score:2, Informative)
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)
Heat as a consideration (Score:2)
In the summer though, that room is a bit warm. I could definately see how a company with se
Just like buying a house... (Score:2)
riser cable and amp gauge (Score:1)
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)
Test (Score:3, Funny)
Or if you're feeling cheap, use These [digikey.com] but don't leave them powered for more than 5 seconds. (read the datasheet).
Heaters or hair dryers are cheaper though (Score:1)
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)
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)
Use a Circuit Breaker Tester (Score:1)
bring in supplemental power (Score:4, Funny)
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)
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.
Re:Use a Multimeter (Score:1)
--Mike--
Re:Use a Multimeter (Score:2, Informative)
I've worked in my profession with high voltages and high wattage loads, actually. It's something that only engineers or fools should be tinkering with. If you don't know what I^2 * R is for, or how to insulate such a rig properly, then don't even think of it.
Sorry, thought it was a physics test (Score:1)
Although
Re:Sorry, thought it was a physics test (Score:1)
You do have more than a theory... I saw one article where a dumpster was filled with water, and electrodes passed a current though the water as a make-shift test load for a small-scale hydro dam.
http://www.eere.energy.gov/power/tech_access/docs/ 37_hydropower_for_remote_alaskan_community.cfm [energy.gov]
Flame Bait! Re:Use a Multimeter (Score:1)
=)
Consider your upgrades for power use (Score:2)
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
How about low power equipment? (Score:2)
Check the supply fuse (Score:2)
Easy. (Score:2)
use ohms law (Score:2, Informative)
Re:use ohms law (Score:1)
This is too easy (Score:2)