Spa sub panel: wiring and connections.

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Old 08-18-16, 11:11 AM
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Post Spa sub panel: wiring and connections.

Hello All, looking for some feedback from those whom have electrical expertise.
I am in the process of installing a new spa sub panel outside of my home. There was a hot tub there previously and whomever installed the 220 for hot tub failed to put a GFI sub panel in and instead directly wired the 220 into the hot tub. I am using the existing Aluminum cable to install a hot tub sub panel. My new hot tub requires a 50 amp GFI sub panel. I am running #6 copper 4 wire from the sub panel to the spa pack.
The Aluminum service wire is approximately 70' and from what I can tell reading the outside it is SE Cable Style R XHHW-2 600V CDRS 8 AWG 1
Does this existing Aluminum cable suffice for my requirements? My spa sub panel indicates that it is compatible with AL. My thought was to ensure I used the AL paste when connecting to the sub panel. Is there anything else that I should be aware of? Thank you!Name:  wireresized.jpg
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Old 08-18-16, 11:20 AM
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Does this existing Aluminum cable suffice for my requirements?
In a single word, no. Number 8 aluminum is rated at only 30 amperes. You need a 50 ampere circuit and that requires number 6 copper or number 4 aluminum.

There are other requirements for hot tubs that also need to be met. Wait for one of the real electricians to comment.

BTW, nominal voltage is 240, not 220.
 
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Old 08-18-16, 11:50 AM
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Thank you for your response, I wonder if the tub that was there prior only required 40amps..
 
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Old 08-18-16, 11:55 AM
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I am running #6 copper 4 wire from the sub panel to the spa pack.
Do you mean 6-3 UF or 6-3 NM-b (AKA Romex). Cable contains a bare ground. Bare grounds are not allowed outside. If NM-b NM-b is not allowed outside.
 
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Old 08-18-16, 12:29 PM
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I wonder if the tub that was there prior only required 40amps.
Still would have been wrong. As I previously stated, #8 aluminum cable has a maximum Ampacity of 30 amperes.
 
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Old 08-18-16, 12:53 PM
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#8 aluminum XHHW-2 is rated for 45 amps. Being that they are installed in a cable it would be required to drop it down to the 60 degree column which would be 35 amps. While 35 amp breakers do exist, I could see an AHJ allowing it to be sized to the next higher breaker, which is 40 amps.

All that said, that #8 aluminum is not big enough for 50 amps.
 
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Old 08-18-16, 01:47 PM
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#6, THHN, 4 separate insulated wires using conduit from the sub panel to the spa.
 
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Old 08-18-16, 01:53 PM
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I'm correct that this is #8 Aluminum right?.....from what I can tell on the cable it says 8
 
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Old 08-18-16, 01:57 PM
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So if I need to rerun this line from the main panel, I can use #8 4 wire cable right....or do I need #6 because the spa calls for #6 ground. Are there any cables that don't leave the ground bare? Because after it comes out the side of my brick wall I need to take it up about 4 feet to feed it into the spa sub panel.
 
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Old 08-18-16, 02:03 PM
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You can use a Chapter 3 wiring method inside, but none will have full size ground.

Once outside the ground needs to be insulated.

I have not seen a tub that did not call for copper conductors.
 
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Old 08-18-16, 02:04 PM
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Are there any cables that don't leave the ground bare?
No.
after it comes out the side of my brick wall I need to take it up about 4 feet to feed it into the spa sub panel.
Use a weather proof junction box where the cable exits and connect a whip with two black #6 and a green #10. If it is 120/240 not 240 then use two black #6, one white #6 and a green #10.
 
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Old 08-18-16, 10:21 PM
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So if I need to rerun this line from the main panel, I can use #8 4 wire cable right....or do I need #6 because the spa calls for #6 ground. Are there any cables that don't leave the ground bare? Because after it comes out the side of my brick wall I need to take it up about 4 feet to feed it into the spa sub panel.
You can use PVC coated MC but by the time you buy the connectors you can have all your conduit paid for.

Don't forget to make sure you have all of your bonding correct. I would suggest reading Article 680 of the National Electrical Code before touching this.
 
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Old 08-19-16, 09:57 AM
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The trade name is TECK cable which is available in an outdoor, insulated ground configuration, but unless you're near a large city the electrical suppliers probably don't stock it.
 
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Old 08-21-16, 02:30 PM
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Question regarding 2 pole GFCI in mane panel ground to neutral bus wiring....

Ok, so I am progressing along in my first DYI electrical involving the main panel in preparation of our new Hot tub which is due to arrive tomorrow!

Previously there was a hot tub installed with a 220, however whomever installed the 220 with a 50 amp breaker decided to use AL #8, and after my research and assistance from others here on the forum I decided to replace this with #6 6/3 with ground CU. Also the prior owner had the 50 amp GFCI in the main panel, however there was no disconnect or outside the home in line of sight of the spa. So I am adding a GFCI 50amp sub panel outside my home.

I just finished running the 85' of 6/3 w/ ground in my basement, wow, that stuff is difficult to work with trying to hang from ceiling, especially by your self.

I wired it into the existing 50 amp GFCI in the main panel. Have a question though after wiring in the new wire and doing it in the same manner the AL was wired. The ground on the 6/3 is now wired into the neutral bus, the same as the additional white wire from the GFCI. I just read on a diff forum that because it is in the main panel this is alright. Just wanted to here a few opinions on that.

The other thing I was hoping those of you with knowledge in this area can speak to. Obviously on this circuit I will essentially have 2 GFCI breakers. Will that cause me any issues? I don't have to have my 2 loads in any particular order when I now wire in my Spa GFCI sub panel right??

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Old 08-21-16, 02:43 PM
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I combined your two threads.

You are correct..... at your main panel it is a combination neutral/ground bar.
At your new spa panel you will not need GFI breakers.

Be very careful.... the grounds and neutrals must remain separate at the sub panel.
 
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