Solution to a Potentially Hazardous Wiring Problem in Melting Point Units In our large organic laboratory we currently use three dozen Mel-TemprM melting points units. We have found them to be much safer and more convenient than the Thiele tube method previously employed. Hat During the examination of a unit which failed recently, we found that the (black) fuse was mislocated. The fuse does not necessarily blow in the event of a short circuit. In theunit which failed the transformer had burnt out due tosuch ashort circuit. If the unit is not rewired, there is considerable shack hazard, particularly if the grounding plug is bypassed. Rewiring the unit is a relatively simple task; the wiring diagram needed is sham helow. The manufacturer is aware of the problem and has agreed to rewire the units with no charge for labor; interested persons should contact the manufacturer: L a h r a t o r y Devices, P.O. Box fi8, Cambridge, MA 02139. Newly Switch manufactured units now are incorporating the safer wiring plan shown. \
F
/-Neutral (white)
-
,Ground (green)
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J a c k E. Leonard Leonard E. Mohrrnann Texas A&M University College Station, TX 77843
Heater
Volume 57. Number 2 February 1980 I 119
