How to correct detached garage sub-panel installation?
My daughter bought a house built in 1941 with a number of electrical issues that concern me but right now I am trying to address what I believe to be a poor installation of the garage sub-panel.
The garage is detached and the sub-panel is a CH2L70SP connected to a 15A breaker from the main panel with what looks like 12/2. Ground and neutral are connected to a common bus. My understanding is that ground and neutral should only be connected at one point typically at the main panel and bonding them at the sub-panel creates an alternate return path for current through anything grounded and should be avoided. Is this correct and if so what do I need to provide an isolated neutral bus?
The garage load consists of lights and outlets and I don't she will need anything more than 15A service there. There are a number of old conduits, wires, etc. that are not connected in the garage (i.e. the old conduit with lots of small wires in photo lower right) that I assume should be removed.
Comments (10)
kudzu9
last yearHU-247834317
last yearlast modified: last yearShe initially thought she would park her RAV4 in the garage and was interested in a garage door opener but last weekend she parked the car there and found that it was too small so she no longer wants a garage door opener. No heat required in the garage. Electric vehicle would require complete new circuit from the main panel (and main panel replacement) so no provisions for an EV (nor do I expect she will be considering one in this house).
Her house is only 820 sq ft with a total of 9 circuits in the main panel and the breakers total only 190A. The plan is to address the cheap things first until she can save up to address the bigger issues in the house (i.e. knob/tube, Sylvania Main Panel, ancient wiring, imbalanced circuits, only 2 grounded outlets, 1 GFCI, etc.). As her dad it scares the heck out of me but people have been living in it for years and I need to take it one step at a time. Here is the main panel (for reference - I have heard these have had serious issues).
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Comments (8)I thought about a main breaker when I was lookin to buy something. But I was told I could just use the breaker in the main that I run this cable from as a main breaker. I was going to run the new wire thru the roof. im going to use the old 14/2 wire thats run thru it to the garage to pull the new wire thru and into the garage. I can see thru the roof from the attic in the house. its open to run wires thru it. How do I hook up the back feed? I really dont think I will ever need more then 6 spaces anyways its only a 1 car garage. I just use it to do some tinkering around. I allready have all new wire run with 6 new outlets around the garge that goes to 1 breaker. And 4 Fluorescent lights on 1 breaker. if I use 2 spaces for a back feed then that leaves me with 2 left for future use. dont think I would ever need them. If I would ever need 240 then that would be my last 2 spaces. Thanks for all your help. Its allways nice to get help. thanks again. Brad...See MoreDetached garage sub panel
Comments (9)I believe this three wire system was to code a few years ago for detached structures.The cable had been connected to an older panel,but was removed when it was decided to convert the garage into a workshop.A newer sub panel was mounted on the wall with a 70 amp double pole breaker and the same size was installed at the main panel.The previous installation seemed to function quite well,but it was hard to find breakers when I wanted to ad to the panel.The cable looks to have 2 #4 insulated aluminum wires with a similar bare ground.The 2 hot wires were connected to the breaker,and I think,but not sure that the ground wire was attached to the common bus bar with the bonding strap removed.All the equipment white wires were attached to the common bus and all the equipment grounds went to the ground bus which was attached to the panel box and to the grounding rod outside the building.Hoping this helps and thanks for any feedback you have....See MoreHow much should a detached garage cost?
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