Excuse me, I did look at the code book as is suggested in your Sticky. The NFPA may answer this question, but I am not knowledgeable enough to recognize it: Our offices are upstairs in an older (renovated home) building with modern wiring. We have 4 computers, 3 printers, and miscellaneous with no problems. Occasionally, my co-worker used a space heater and during those times, using the shredder, starting a coffeemaker, etc. would trip the breaker. Later, we plugged in a refrigerator (without problem) and added a microwave. When using the microwave, everything is okay unless someone starts the coffeemaker, etc. - that trips the breaker. If the refrigerator compressor cycles on,while using the microwave, that trips the breaker. The biggest problem with all that is simply that our computers shut down in the middle of ongoing work. The breaker is a 20 amp. Can I just replace it with a higher one like 30 or so? Thank you, Sheila

Hi Sheila, this might help if you want to take a lookhttp://electronics.howstuffworks.com/circuit-breaker.htm

Sorry but you can just increase the size of the breaker. The wiring should be matched to the breaker and it would be unsafe and out of code to put in a bigger breaker. Heavier wire might be pulled but I'd vote for a new circuit to be run from the panel to the office.

That can be a fire hazard if you do that. You have to sacrifice some things or buy a UPS (uninterrupted power supply) system for each computer. This will keep your computers on long enough to reset the breaker.

Refrigerator should be on its own circuit. Microwave would be good on own as well as office. 20 amps large as you can go on recepticles you speak of.
Do you have spaces left in your panel, and do you have attic or basement, do you see easy way for person to get wiring from panel to kitchen?
If done in conduit, you or someone may be able to pull circuits through conduit with no destruction.

As a side note, I would suggest looking into UPS devices to help protect your computers. One for each workstation is preferred.
"The biggest problem with all that is simply that our computers shut down in the middle of ongoing work"

A UPS device (AKA Uninteruptible Power Supply) basically acts as a surge suppresor with a battery backup. They can be bought fairly cheap these days.

Some UPS devices will also act as a voltage regulator so if there is a brown out, the battery kicks in to supplement the power. Others will run the power through the battery all the time to supply a consistent supply.

UPS devices can also be used for other purposes than computers, I run all of my DirecTV receivers, DVD and VHS players as well as the TV's (LCD/Plasma/regular tube type) through them so that if there is a power flicker I won't lose any of the programming or have that annoying 12:00 blinking at me all the time.

Hope this helps with part of your problem.

Sheila,

I don't want to rain on your parade but would you be so kind as to define your wiring.

Start at the rated service in to your floor. For example, are you on your own meter or is there one meter and panel box for the entire building. If you are on your own meter, that what is the rated amperage for your panel box.

Now with the bulk ratings out of the way, how do you know what is on a circuit and what is on another circuit. Just because you see an outlet does not mean it is on the same circuit as another outlet.

In general you seem to be experiencing problems generally associated with low power. Also, the appliances you are describing microwaves, refrigerators all have what is know as an "Instant on Current" this is at the start of a cycle and can cause strange things to happen.

My suggestion is to get licensed electrician to inspect the wiring from the panel to your floor and throughout your offices. There are ways to balance load requirements within your offices to reduce their impact on other circuits but you might really need more power.

Oh, by the way, it's the "National Electric Code" NEC that is the bible here in the U.S.

I am understanding this is all on one circuit, and not your main breaker. A combination of the above will easily trip a 20 amp, You need more circuits.

Sheila,

A UPS is a wonderful marketing gadget, but unless you actually have backup power it will still go toes up.

Most computer manufacturers and periphery; (printers) use what is called a "Switchable" power supply, This means that the P/S will work as designed within a given range. Usually 10%. If the incoming signal drops below the low threshold or above the threshold, the power supply switches off to protect the unit.

Some companies, IBM and Lexmark would tell you not to use them because they could cause, more problems then they were worth. Chief among them would be the false sense of security that your data was safe and periodic back-ups were not needed.

In both IBM and Lexmark cases warranties were void if the damage was caused by a UPS.

However, in honesty, it has been over two years since I was in the labs for IBM or Lexmark and things may have changed.

Again, I am very suspect that your demand at peak times is the cause of your problems.