Area classification
Area classification
(OP)
Area classification and T -rating. I see electrical equipement with "T" ratings. What about standard motors? Is it proper to use the insulation class plus a 20 degree hot spot to dervie a "T" rating?





RE: Area classification
RE: Area classification
RE: Area classification
(UL= Underwriters Laboratories Inc.)
Motors Listed by UL must bear clearly
Class ( I, II, III)
Group ( A,B,C,D,F,G)
Division (1,2)
Operating temperature ( T1,T2,T3, etc)
The motor classification stamped on the motor plate should match the hazardous atmosphere of the intended location.
RE: Area classification
RE: Area classification
RE: Area classification
RE: Area classification
Flameproof motors have different rules of engagement. They have to contain the energy of any potential explosion and any gases that escape have to be cooled down to prevent ignition. Thus flp motors tend to be big thick and heavy.
djs statement about most TEFC motors being suitable for cl1 div 2 is a generalisation and if anti-condensation heaters are fitted then they should be changed, and this is usually a simple mod.
RE: Area classification
RE: Area classification
Since these are considered to be “General Purpose Equipment” they require no special marking either – See Section 500.8(B)(6)(a).
To answer the OP though, considering the operating temperatures should nevertheless be a consideration. See Section 501.125(B) FPN No. 1. While FPNs are not technically part of the NEC, failing to observe them is foolish. NEMA MG-1 will detail the various “rises” given motor designs with specific insulation systems will have on internal and external surfaces.