Hi, I design industrial electrical PLC control systems for a living. However, I am personally installing a hot tub inside my house and had a few questions I was wondering if I could bounce off some of you. I am getting the room ready for installation. I am reading the electrical requirements that the tub manufacturer has provided. It says I need to provide a 240 Volt 60 amp GFCI breakered 2 wire w/ ground circuit along with a maintenance disconnect. OK, so far so good. I understand all of that except maybe what size of wire I am supposed to use. In my job we use the same size wire for PLC control circuits and it has been a long time since I sized wire using table 310-16.
My first question is, even though I am going to use THHN, something in the back of my head from when I used to do residential work is telling me that I have to use the 60?C column to size. Is this correct, or am I thinking of something else? If it is, that would mean I would need #4 copper. Or am I wrong about the 60?C and I need #6 copper, which is what the other two columns require.
My next question comes after reading a bit further in the pamphlet that the manufacturer has provided and I read the following:
?when using wire larger than #6 (10mm2), add a junction box near the spa and reduce to short lengths of #8 (8.4mm2) wire between the junction box and the spa."
According to the way I interpret this, if my wire size is #6 then I can bring that all the way to the hot tub from the maintenance disconnect. However, if it is #4, then I have to reduce it down to #8s. Why wouldn?t I be able to reduce it down to #6s if it was good enough to run straight in before? and is this legal to reduce it down to #8s like a tap rule or something?
Thanks in advance for your time.
Jak
My first question is, even though I am going to use THHN, something in the back of my head from when I used to do residential work is telling me that I have to use the 60?C column to size. Is this correct, or am I thinking of something else? If it is, that would mean I would need #4 copper. Or am I wrong about the 60?C and I need #6 copper, which is what the other two columns require.
My next question comes after reading a bit further in the pamphlet that the manufacturer has provided and I read the following:
?when using wire larger than #6 (10mm2), add a junction box near the spa and reduce to short lengths of #8 (8.4mm2) wire between the junction box and the spa."
According to the way I interpret this, if my wire size is #6 then I can bring that all the way to the hot tub from the maintenance disconnect. However, if it is #4, then I have to reduce it down to #8s. Why wouldn?t I be able to reduce it down to #6s if it was good enough to run straight in before? and is this legal to reduce it down to #8s like a tap rule or something?
Thanks in advance for your time.
Jak
