0

I am upgrading an obsolete Sylvania panel located inside the house. There's a main panel outside the garage with the main 150 amp breaker. I have a supplied bonding screw with the new panel. Technically the indoor panel is a sub panel, so I am thinking I shouldn't install the bonding screw. Am I right in my assumption?

The house was built in 1986. The house is located in Florida, USA. What should I look for to know, should I check for 4 wires from outside feed to the inside and see if outside box is bonded neutral to ground?

isherwood
  • 119,766
  • 7
  • 148
  • 349
Ken
  • 5,323
  • 2
  • 11
  • 27
  • Can you post photos of the insides of the existing panel(s)? – ThreePhaseEel Jun 04 '21 at 11:33
  • 1
    Does this answer your question? [Is it ok to have mixed grounds and neutrals on bars in a breaker box?](https://diy.stackexchange.com/questions/1706/is-it-ok-to-have-mixed-grounds-and-neutrals-on-bars-in-a-breaker-box) – isherwood Jun 04 '21 at 12:41
  • Hmm. 1986? If your garage is a separate structure then you could only have 3 wires between buildings and bonding at the next panel. – NoSparksPlease Jun 04 '21 at 12:47
  • @isherwood it does as long as the understanding is just that I have a breaker box with the main breaker and only that breaker in it on the outside of the house - that is considered a main panel and the indoor panel a sub panel. – Ken Jun 06 '21 at 12:55

1 Answers1

8

You are correct--the panel should not be bonded. Most panels will come with a bonding screw in case it is being used as a main panel and first means of disconnect, which yours isn't. When you install your sub panel, all neutrals from circuits in the panel need to be attached to the neutral bus and a second grounding bus needs to be installed in the sub panel and all bare and green grounding conductors must be install on that bus.

Also the neutral conductor coming from the main panel needs to be attached to the sub panel neutral bus and the grounding conductor coming from the main needs to be attached to the new grounding bus. Most panels do not come with a separate grounding bus but can be purchased separately. They are usually available at the same location you purchased the sub panel.

Hope this helps and stay safe.

isherwood
  • 119,766
  • 7
  • 148
  • 349
Retired Master Electrician
  • 13,041
  • 10
  • 31
  • @isherwood I replaced the panel, but I now have an issue, one light in the house will change its intensity enough to notice about every 30 seconds but only when AC is on. Both circuit s are on left side . The lights I had a short wire so I moved the position up a few notches. Iam thinking my routing is causing the issue, but will double check the tightening. Not sure on the torque required for the mains connection screws. What's causing the issue with 6one light ? – Ken Jun 05 '21 at 08:54
  • I replaced the panel yesterday; breakers and grounds sat lower, I did not have a cable stretcher :(; Many grounds were short by about 6 to 8 inches, I individually wire nutted an extension on them so I could ground the circuits. Should I have scraped the paint under the grounding bars ? Also I have an issue with one light - it changes intensity (noticeable , not like a brown out - just you know it dimmed a little and got back to normal - it is cyclic only when the AC is on) possibly how I had to route this wire ? Any guidance on troubleshooting that condition appreciated. – Ken Jun 05 '21 at 22:51
  • 2
    It's not my answer, and please don't ask new questions in comments, especially on resolved posts. Ask a new question. – isherwood Jun 07 '21 at 12:41