Expert: Don Beck - 9/10/2007

Question
I'm replacing an old hot tub with a newer one.  The wiring for the previous tub was 240v, run in a conduit from a 50amp circuit breaker on the main panel out to the outdoor  hot tub.  There are 4 wires in this conduit 2 line feeds (both 8ga black copper in this case) there is a neutral (white 10ga) and a ground (green 12ga -  previously there was no GFCI or disconnect panel.  I've added one about 11 feet from the hottub itself mounted on the brick house wall.  My questions are 1) are the neutral and ground wire adequate thickness, I thought they should be 8ga like the line supply?  2)The two line supplies (both black) are interchangeable, right?  They are just opposing polarity 110v which are combined to create the 220 circuit?  In modern circuits they are differentiated Red and Black, is this a problem that they are both black?  3)My new spa is a 3 wire connection, is this going to create final connection problems since I have four wires?

Thanks for your help.

Chris  

Answer
Hi Chris,

1). It was common practice a few years ago to downsize the neutral. It is best to have the neutral the same size as the hot feeds.

2). Yes, they are interchangeable and can be of the same color.

3). The 4 wire feed should be fine. Your new spa probably doesn't require a neutral. A lot of the newer 220 V devices don't. It should say in your instruction sheet whether a neutral is required or just the 2 hots and the ground. Neutrals on 220V devices are only needed if there is something that requires 110 Volts, like a digital readout.

Don