CSA C22 2 NO 155-M1986-1986 Electric Duct Heaters (First Edition General Instructions No 2 4 1987 Update No 3 12 2008).pdf

1、C22.2 No. 155-M1986(reaffirmed 2013)Electric duct heatersLegal Notice for StandardsCanadian Standards Association (operating as “CSA Group”) develops standards through a consensus standards development process approved by the Standards Council of Canada. This process brings together volunteers repre

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15、OLEPURPOSEOFREVIEWINGITsSEARCHANDBROWSETHISDOCUMENTANDsPRINTTHISDOCUMENTIFITISIN0$(b) bare live parts; and(c) parts of the heater assemblies (eg, sheath, heating element supports) the surface temperature of which exceeds 280C.4.1.8.2 Guards shall be of rigid construction and shall be held in positio

16、n by screws or by some equivalent means, so as not to be readily detachable. Guards shall not be detached from heaters for shipping purposes.4.1.8.3 Guards shall have sufficient physical strength to retain their shape even under conditions of excessive physical strain that may occur in ordinary oper

17、ation and handling. The size and shape of the guard and the degree of compression of the guard necessary to cause failure of the heater under the abnormal temperature test conditions shall be considered.4.1.8.4 The adequacy of guards for duct heaters that are located within 1 m of the ends of warm a

18、ir ducts shall be judged with respect to their general serviceability, and with respect to the shape and size of the openings in them, in conjunction with the distance of the guard from the heater element. Except as otherwise noted in Clauses 4.1.8.5 and 4.1.8.6, openings in guards will be acceptabl

19、e if the following conditions are complied with:(a) The shape and size of an opening are such that a test gauge in the form of a right circular cone having a base diameter of 70 mm and height of 140 mm is prevented from touching the parts detailed in Clause 4.1.8.1 when the gauge is inserted, apex f

20、irst, in any manner.(b) The shape and size of an opening that permits the vertical downward entrance of a bar 12.5 mm wide and 1.5 mm thick are such that a test gauge 1.5 mm thick and in the form of an isosceles triangle having a base of 70 mm and a height of 140 mm is prevented from touching the pa

21、rts detailed in Clause 4.1.7.1 when the gauge is inserted, apex first, in any manner.The testing of an opening with this triangular gauge shall apply also where the vertical downward insertion of the bar is prevented either by the construction of the guard or by the use of an additional barrier, unl

22、ess the vertically applied bar tends to be deflected outward (ie, away from the guard).(c) The area of an opening in a substantially vertical face of a guard is not more than 2100 mm2where the size and shape of the opening permit the entrance, from any horizontal direction, of a vertical rod 1.5 mm

23、in diameter and 70 mm long.11(Replaces p. 11, September 1986)C22.2 No. 155-M1986 Canadian Standards AssociationDecember 20084.1.8.5 Openings in the area covered by a guard shall not be located directly below open coil type heating elements or other bare live parts of the heater element unless such p

24、arts are baffled.Note: This requirement does not apply to heating elements enclosed in metal, quartz, or a similar sheath regardless of the sheath temperature.4.1.8.6 Unless the heater assemblies or heating elements of floor insert duct heaters are constructed or baffled so that combustible material

25、s or litter cannot drop on the elements, the guards shall be constructed to prevent a straight rod of circular cross section, 6.4 mm in diameter, from being inserted so as to touch the heater assemblies.4.1.8.7 Heater assemblies that are installed at least 1 m from any accessible opening of the duct

26、 and that are marked in accordance with the requirements of Clause 5.13 may be exempted from the guarding requirements of Clause 4.1.8.1.4.2 Protection Against Rusting and Corrosion4.2.1 Iron and steel parts shall be protected against rusting in a suitable manner. (See also CSA Standard C22.2 No. 0.

27、)4.2.2 The surfaces of metal parts shall be protected, if necessary, against scaling, flaking, or other effects of corrosive action that might cause subsequent reduction in the dielectric strength or reduce spacings below those required by Clause 4.14 while in normal use.4.3 Mechanical Assembly4.3.1

28、 Parts used in the construction of heaters shall have adequate strength and shall be assembled and secured in position to ensure acceptable functioning under the most severe conditions likely to be encountered in service.4.3.2 Switches, lampholders, thermostats, etc, shall be fastened securely and r

29、igidly to maintain the spacings required by Clause 4.14.4.3.3 The operating mechanism of switches or controls shall not subject electrical parts to undue strain.4.3.4 Screws or other means of fastening fragile insulating parts shall not be so tight as to result in cracking or breaking of such parts

30、due to expansion and contraction, unless the insulating material is completely retained. Generally, such parts shall be slightly loose or shall be provided with cushioning material.4.4 Supply Connections4.4.1 Supply connections shall be made within either terminal or outlet boxes, or they may be mad

31、e within the enclosure of duct heaters provided that the area is free of moving parts such as fan blades.(Replaces p. 12, September 1986)12 Canadian Standards Association Electric Duct HeatersDecember 20084.4.2 Supply connections intended to be made within the enclosure of the duct heater shall have

32、(a) the supply connections confined to a designated area by the use of a terminal box or barrier;(b) a degree of enclosure not less than that required by Clause 4.1; and(c) the thickness of the sheet metal where the conduit or armoured cable is attached not less than 0.78 mm thick if of steel and no

33、t less than 1.08 mm thick if of nonferrous metal.4.4.3 The location of terminal boxes or compartments in which supply connections are made shall be such that the connections will be readily accessible for inspection after the duct heater is installed as intended, but not without opening a cover, whi

34、ch shall be adequately secured by at least two screws or their equivalent. Electric parts shall not be attached to such covers.4.4.4 Terminal Parts4.4.4.1 Wire-binding terminal parts and the identification of terminal parts and leads shall comply with the requirements of CSA Standard C22.2 No. 0, ex

35、cept that terminal screws may be of suitably plated ferrous material in all screw sizes. (See CSA Standard B35.2.)4.4.4.2 Wiring terminals shall be prevented from turning. Friction between surfaces is not an acceptable means of preventing the turning of terminal parts.4.5 Electrical Insulation4.5.1

36、Bare live parts shall be supported on heat resistant, moisture-absorption-resistant insulating material that is suitable for its particular application and will withstand the most severe conditions likely to be encountered in service.4.5.2 The acceptability of insulating material shall include consi

37、deration of all the following:(a) mechanical strength;(b) dielectric strength;(c) insulation resistance;(d) heat- and moisture-resistant properties;(e) degree of enclosure or protection; and(f) other factors that might have a bearing on the fire and accident hazards under conditions of actual use.No

38、te: Material such as mica, porcelain, phenolic composition, cold-moulded, and certain refractory materials are generally acceptable as the sole support of live parts. Other materials that are not suitable for general use, such as asbestos and magnesium oxide, may be accepted if used in conjunction w

39、ith other more suitable materials, or if located and protected so that exposure to mechanical injury and the absorption of moisture are prevented.12A Canadian Standards Association Electric Duct HeatersDecember 20084.15.3 Terminals at the point of supply connections for bonding heaters to ground sha

40、ll be accessible for inspection and maintenance.4.15.4 Bonding conductors in heaters shall have insulation equivalent to that of live conductors if there is any likelihood of accidental contact with bare live parts.5. Marking5.1 Duct heaters shall be plainly marked, in a permanent manner, and in a p

41、lace where readily visible after installation, with all the following:(a) manufacturers name, trademark, or other recognized symbol of identification;(b) catalogue, style, model, or other type designation;(c) voltage and maximum current;(d) if suitable for use on ac only, the letters AC and C.A. aft

42、er the voltage or the words FOR AC ONLY and POUR C.A. SEULEMENT if elsewhere in the marking; or the frequency in hertz if the heater is frequency-sensitive;(e) output in watts;(f) the output-air temperature limit;*(g) specification of minimum clearance to combustible material, maximum input air temp

43、erature, and minimum air velocity;(h) electrical rating of the limit control where external contactors or relays are used;(i) electrical rating of relay coils;(j) electrical rating of fan or blower control; and(k) such other marking as may be necessary to ensure safe and proper operation, and instal

44、lation.*Not to exceed 93C.In connection with manufacturers specified minimum air velocity, see Clause 6.4.3.3.5.2 Markings shall comply with CSA Standard C22.2 No. 0.5.3 Duct heaters that depend on proper location or position for acceptable operation shall be marked (eg, TOP and HAUT or BOTTOM and B

45、AS) to indicate how they shall be installed.5.4 The marking CAUTION: USE SUPPLY WIRES SUITABLE FOR . . .C and ATTENTION : EMPLOYER LES FILS DALIMENTATION APPROPRIS POUR . . .C or the equivalent wording shall be located near the supply entrance or on the nameplate if the temperature in the terminal b

46、ox or the compartment intended for the supply connections exceeds 60C in the normal temperature test. The number to be marked in this caution shall be 75, 90 or 110 for temperatures of 6175C, 7690C, or 91110C, respectively.5.5 The marking WARNING: DISCONNECT ALL SUPPLIES BEFORE WORKING ON ANY CIRCUI

47、T and AVERTISSEMENT : DCONNECTER TOUTES LES SOURCES DALIMENTATION AVANT DE TRAVAILLER SUR UN DES CIRCUITS or equivalent wording shall be marked on equipment for which supplies of different circuits have been permitted.17(Replaces p. 17, September 1986)C22.2 No. 155-M1986 Canadian Standards Associati

48、onDecember 20085.6 Terminal points where field connections are made to supply and control circuits shall be clearly marked.5.7 The direction of air flow shall be shown on the heater, if essential to proper functioning.5.8 The maximum number of duct heaters to be mounted in series in a duct shall be

49、indicated.5.9 The duct heater shall be marked with the following or equivalent:CAUTION: THIS DUCT HEATER SHOULD BE INSTALLED IN SUCH A MANNER AS TO PERMIT REMOVAL WITHOUT SERIOUS DAMAGE TO THE BUILDING STRUCTURE, SERVICES, OR FINISH OF THE DUCT HEATER ITSELFandATTENTION : CET APPAREIL DE CHAUFFAGE GAINES DEVRAIT TRE INSTALL DE SORTE QUIL PUISSE TRE ENLEV SANS CAUSER DE DOMMAGES I