trying to classify an LP area to determine the boundaries for protection in the NEC. this is waaaaay confusing.
first question is where to measure from. is it anywhere on the length of the tank, all fittings associated with the tank, only the transfer point from the tank to the bottles?
dispenser, dispenser enclosure, dispenser base are all used to define the classified areas in table-514.3(B)(2)..... did i miss the definiton of dispenser somewhere?
then what articles apply to figure the distances for protection from pole lights or canopy fluorescents or parking lot receptacles? from what i read, if they are outside the class I div 1 or 2 areas in the table in 514.3, they are ok.
i eliminate articles 502 for dusts, 503 for class 3 like sawmills and textile mills, 504 I.S. systems, and 505 the IEC zones.
i think 500, 501, and 514 apply.. and NFPA 58 LP Gas Code, but don't have that one.
lots of things apply, but here's my important list, please add to it if something key is missing.
500.7(A) only Explosionproof is used in Class I [not Dust Ignitionproof, or Dusttight]
500.8(A) equipment to be identified
500.8(D) only NPT threading taper 3/4" per foot [hmmmm, not metric!! guess it hasn't been sprinkled by the imperial pixie dust yet] wrenchtight and listed fittings for threaded conduit.
500.9 sends you to 510 thru 517 for specific occupancy types
501.1 Class I applies to propane, gasoline, methane, acetone, hydrogen, etc
501.4 Class I locations use threaded RMC or steel IMC, 5 NPT threads engaged [excp. RNMC ok in concrete], listed 3' flex at motors is ok,
501.4(A)(3) all boxes, fittings, & joints to be approved
501.4(B)(1-3) wiring methods
501.4(B)(4) boxes, fittings, joints ok if not explosionproof at outlets or enclosures w/o arcing
501.5(A)(4) Class I Div 1 Boundary, conduit leaving sealed w/in 3.05 m [10 ft] of boundary, ok for pipe to pass thru if w/o fittings and 300 mm [12 in] outside boundary
501.5(B)(2) Class I Div 2 Boundary, conduit leaving sealed w/in 3.05 m [10 ft] of boundary, ok for pipe to pass thru if w/o fittings and 300 mm [12 in] outside boundary
501.5(C) Class I Div 1 & 2
501.9(A) Class I Div 1 luminaires (B) Class I Div 2 Luminaires
501.12 Plugs & Receptacles
501.13 THWN is typical for exposure to liquids
501.14 Signaling circuits
Table 514.3(B)(2) LP Classified Areas,
Class I Div 1 is enclosure & 450 mm [18 in] from dispenser to 1.2 m [4 ft] above dispenser base; and entire pit beneath and w/in 6.0 m [20 ft] horizontally from dispenser if pit isn't mechanically ventilated;
Class I Div 2 is 450 mm [18 in] aboveground and w/in 6.0 m [20 ft] horizontally from dispenser enclosure including pits when mechanically ventilated.
514.7 refers to 511.7 for wiring above Class I locations: arcing equipment, switches, motors, but not receptacles or lamps, less than 3.7 m [12 ft] above floor to be totally enclosed or explosionproof; lights to be 3.7 m [12 ft] above floor or totally enclosed or explosionproof.
is there always a pit with LP???
too much stuff spread out in too many places