Ask 'Dr. Spa' Q & A Message Board

This is easy to check. You want to examine the electrician's wiring for type (ie., THHN, THWN-2, etc. and stranded, not solid copper conductors) and size. Hot Springs MINIMUM wire recommendations are stranded wire rated at 75 C or higher of the appropriate wire size. The actual wire size selected by the electrician is based on many factors such as length of wire run, highest ambient temperatures encountered, etc. Electrician's will frequently goof and install a 60 C rated wire such as UF or NM-B because it is cheaper and they generally have plenty of it on their truck. Such wire does not generally have the requisite ampacity and is generally solid copper rather than stranded. The terminal block, which is spring loaded, cannot get as good a connection to solid copper as it can with stranded copper. Another big goof to watch for is the use of aluminum wire which will cause the same issue due to incompatibility with the terminal block.

A load/no load test is performed with a voltmeter. Take a no load voltage test of the circuit first as a point of reference. This is done by immediately reading the voltage when power is first applied, but before any motors or the heater is running. Once you establish that parameter, turn everything on (pump or pumps and the heater) and retake your voltage measurements. It is normal for the voltage to drop a bit under full load as compared to the no load reading. A good circuit only drops about 2 percent maximum under full load. If you start with a no load reading of 240 volts, the voltage on a good circuit may drop to approximately 235 or 236 volts. Any drop beyond that indicates problems in the circuit. There are many causes of excess voltage drop. Some common reasons are incorrect wire sizing by the electrician, a maxed out house service and/or power distribution problems from your electric company (ie. poor service on street, bad nearby transformer, etc.).

Different brands of tubs specify differing levels of acceptable voltage drop. As I said, HS specifies 3 percent max.

John

: John, since I am not an electrician can you please help me better
: understand your response? I agree that this many boards failing
: identically everytime does indicate SOMETHING is not right. When you
: say "wire type" just exactly what do you mean AND what TYPE
: should I have?
: What is a load/no load test? What kind of meter do you use to conduct
: this test? A friend of mine has electrical meters and such, perhaps
: he could conduct this test for me? This is a 220 line so I dont want
: anyone fried krispy kritter doing this test. thanks!!