as an E.engineer, i can perhaps break it down into simpler terms which may perhaps. for reference, this is set up much in the same manner as i would go about examining any circuit i might be working with, regardless of size or complexity. (i work on a regular basis with 2350kW turbine generators and the large motors that they supply, for industrial corporations) due to several factors, and our good friend james watt, we know that one watt is equal to one joule per second, or one newton-meter (which is regarded as unimportant unless your a thermodynamic technician. for our purposes electrical power is equal to the electromotive force (voltage) multiplied by the electrical current (amperes) ------------------------------------------------------------------------------------------------------ SO 1 Watt = 1 Volt x 1 Amp if we have a 30 watt cfl (i hardly ever see cfls above 30, props for finding em) we can do this 30 watts = 120volts (standard in the u.s.) times Amps (A) 30 = 120A 30/120 = A A = 0.25 amperes of current however if you're going to use an average amount (lets say 5) so that leaves us with 30 x 5 = 150 150 = 120A 150/120 = A A = 1.25 amps continuous soooo..... if you're going to be running these guys on continuously, you're going to draw 1.25 amps of current. how does this relate to wiring and electrical fire safety? Glad you asked! you see, wire is usually rated for its gauge (or diameter) in reference to how much current (amperes) are able to safely pass through without excess amount of resistance (given off in the form of heat). electrical extension cord comes in a variety of sizes, with the number patterns following the usual A -B system where A = the gauge of the wire used and B= the number of conductors (wires) used in most all cases, there are either 2 or 3 conductor cables available at home depot, wal-mart etc... (one hot, one neutral always, with some coming with a ground wire) the safety regulations for the most common extension cord sizes are usually as follows, with sizes, conductor numbers, current capacity and cable length detailed: 16-2 (sixteen gauge with 2 wire conductors) 13A at zero to fifty feet 10A at fifty to one hundred feet 16-3 ( sixteen gauge with 3 wire conductors) same as above 14-2/3 15A zero to fifty feet 13A fifty to one hundred feet 12-3 (almost always found with 3 wire conductors) 15A @ zero to one hundred feet and 10-3 (good luck finding ten gauge two wire conductor) which is good for anything up to and usually exceeding alittle bit 15 amps at zero to one hundred feet Usage of GFCI (Ground fault circuit interrupt) is HIGHLY recommended, even to those who have their grow up wired directly to their circuit breaker, as gfci devices will shut down the power if even trace amount of electricity are leaked to ground (very bad timeeee) even too small for your breaker to detect and shut off. these are easy to install and set up as portable gfci are usually plug and go. ---------------------------------------------------------------------------------------------------- Good common sense, along with placing bulbs no closer than one inch or so from all surround material, using correct gauge connector wire, proper electrical connections, insulation from water and dampness, and use of a GFCI can reduce and eliminate any and all electrical and hazards that might effect your oh so important grow operation