i am a first year apprentice and i really enjoy the site.. i have a question???when above finished floor is specified on blue print,,,does that mean that your measurement should be taken from floor to the bottom of your box ,,or the center of your box???thanks for your replies....

smokey,- I always go to the top of the box.

If it is a commercial job the heights for devices are usually called out in the Specifications. Very seldom do I take it for granted that the engineer looked at the millwork drawings.I usually take the time to make sure that the height called out on the drawings will work with the architectural drawings

in oregon the ADA disabilities requirement comes from a UBC building code section and the inspectors messure 15" from FF level to the bottom of the receptacle openings, both data-comm and line voltage... the switch heights are lot more complicated but mostly 48" to the top of the switch is maximum... 54" if you can parallel park your wheelchair next to the devices.... but usually the plans i see will say "AFF...to center" ... in practice though, we usually set receptacle boxes 18" AFF to centers

As has already been said this should be spelled out somewhere on the prints or in the specs.

Most of the prints we get use the center of the box, however for fire alarm devices they give us the height to top of the device which is different from the height to the top of the box.

Do not forget that AFF includes floor finish too, so if you are roughing in do not forget to add the height of the floor finish.

Hello smokey

All of us are always learning, in this industry the changes and scope of work are almost endless. Keep asking questions, the only 'dumb question' is the one you do not ask. Attend seminars, take classes if you can and there are plenty of sites on the web for information.

Good Luck

Pierre

the answer is? it does not always mean to bottom, as stated by others, always check PLANS & SPECS each time! GEO