J. ARONSTEIN, CONSULTING ENGINEER
MECHANICAL AND MATERIALa ENGINEERING
BME, MSME, Ph.D, N.Y.S. P.E. LIC. NO. 39860
50 PASTURE LANE, XPOUGHKEEPSIE, N.Y. 12603   
PHONE: (914) 462-6452

 William H. King, Jr., Director
   March  29, 1996
 Div. of Electrical Engineering
 U.S. Consumer Product Safety Commission
 4330 East West Highway Rm 611 North Tower
 Bethesda, HD 20814

Subject: Failures of Ideal #65 "Twister" in UL4S6C Heat- Cycle Test.

 Dear Mr. King:

 Previous communications (113/96, 1/23/96) noted that one of the Ideal #65 connections failed the UL486C heat cycle test. That connector exceeded the limit of 125 C maximum temperature rise above ambient. The test was continued  to 250 cycles, with a second connector failing by exceeding the UL4S6C +/- 10 C "stability" requirement. The data for that connector, for every 25th cycle, is summarized below

  Cycle#	d 	S
   25 		13 	-11.9
   50 		16 	- 8.9
   75 		15 	- 9.9
   100 	19 	- 5.9
   125 	24 	- 0.9
   150 	27 	2.1
   175 	33 	8.1
   200 	35 	10.1
   225 	32 	7.1
   250 	35 	10.1

   average "d"= 24.9
where: "d" is the deviation (connector temp. minus control conductor temp.)
 "S" is the difterence between the individual "d" and the average "d".

 With two of the four connectors having failed by 250 cycles, that test run was discontinued. The spread of readings for the second failure precludes its passing of the stability requirement if the test were run to the full 500 cycles per UL4SGC, even if the progressive deterioration was to suddenly stop. Please call me if you have any questions regarding these tests.
    
    Jesse Aronstein, Ph.D, P.E.

 cc: P Sawyer, Ideal Industries,  T. Castino, U.L.