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