When is a Main not a Main?

By
Home Inspector with JRV Home Inspection Services, LLC HOI 394

Electricity is some what of a mystery to most people. All those wires can look pretty confusing and intimidating. The truth is every wire has a proper place. In a main electric panel there are only a few places where each wire belongs.

There are usually three wires in every house circuit. A hot (black or red wire), neutral (white) and ground, (bare or green). Each wire has a specific place and function. Connecting wires together that should be kept separate can have bad consequences. These may be immediately apparent, seeing big colorful flashes and sparks or latent, typically after someone gets hurt.

One of the most frequently found problems in a main or sub-panel is a defect of the latent kind. This is when the panel is not correctly grounded.

The main service panel pictured is wired wrong. It has been this way from day one, about 20 years! The panel is in a multi unit condo building.

What's wrong is this main panel is actually a sub-panel being used as a main panel. Therefore it has to be wired as a sub-panel.

What's the difference between a main panel and a sub-panel panel? The simplest explanation is feed wires. Every panel whether main or sub has main feed wires. As the name implies these wires "feed" the panel all the current for the distribution circuits.

In a main panel there are three feed wires and in a sub-panel there are four. This is a very simplified explanation. In both a main and sub panel two of these wires are hot and feed current to the panel to distribute to the branch circuits. The other common wire is the neutral. This is where it gets complicated.

In a main panel the neutral is wired to a terminal shared with the ground wires. That terminal is bonded (an electrical term meaning it is in contact with) to the panel itself.

In a sub-panel the neutral is wired to a terminal that is separate and isolated from the ground wires and the panel. That extra fourth wire is a ground which is wired to its own terminal bonded to the panel. Check the diagram for a visual explanation.

Getting back to the "main" panel in the picture. The problem is the fourth wire is connected to the same terminal as the neutral. You can see this in the upper left corner of the panel. This in effect renders the panel and the system ungrounded. This is a problem you will only know about after someone gets hurt or, as was the case here, a home inspector discovers it.

James Quarello
JRV Home Inspection Services, LLC

To find out more about our other high tech services click on the links below:

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Posted by

James Quarello
Connecticut Home Inspector
Former SNEC-ASHI President
JRV Home Inspection Services, LLC

 ASHI Certified Inspector

To find out more about our other high tech services we offer in Connecticut click on the links below:

Learn more about our Infrared Thermal Imaging & Diagnostics services.

Serving the Connecticut Counties of Fairfield, Hartford, Middlesex, New Haven, Southern Litchfield and Western New London.

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Rainmaker
1,244,485
Steven L. Smith
King of the House Home Inspection, Inc. - Bellingham, WA
Bellingham WA Home Inspector

Mr James,

Like my Godmother, this just goes whoooooooooooooooooooooosh, right over Nutsy's head. I will stick to walking wires.

Your life coach, Nutsy

Mar 11, 2009 02:10 PM #3
Rainmaker
1,839,579
Jay Markanich
Jay Markanich Real Estate Inspections, LLC - Bristow, VA
Home Inspector - servicing all Northern Virginia

James - it is interesting that no new appliance in the last 20 years torpedoed that main...   so to speak.

Mar 11, 2009 10:36 PM #4
Rainmaker
683,909
James Quarello
JRV Home Inspection Services, LLC - Wallingford, CT
Connecticut Home Inspector

Charlie,The main breaker is at the meter with 5 more for each unit. That is SOP for almost every condo here in CT. And yes technically it is a remote or sub-panel. But without getting to deeep into electrical semantics it is the main panel for the unit. That's when a main is a sub that is a main. You asked and I delivered. :)

Barbara,I would not consider you either of those characteristics. I'm quite certain you could drop some stuff on me that would make my head spin.

Nutsy, I'll aim lower next time.

Jay, For all I know it did. I have found this same problem in many condos here.

Mar 11, 2009 11:34 PM #5
Ambassador
1,333,380
Charles Buell
Charles Buell Inspections Inc. - Seattle, WA
Seattle Home Inspector

James, I have yet to find ANYTHING that doesn't go over Nutsy's head----well, except barbeque sauce maybe.

Mar 12, 2009 02:01 AM #6
Rainer
86,824
Mike (Inspector Mike) Parks
The Parks Consulting Group, LLC - Circleville, OH
Inspector Mike

The system is 'grounded'. What you have here are paralleled conductors. You have 'neutral' current on the 'bare' conductor.

You are missing the equipment grounding conductor (effectively).

Is this panel bonded? I could not tell.

The breakers will work as designed.

Yes this needs to be repaired.

Mar 12, 2009 03:11 AM #7
Rainmaker
683,909
James Quarello
JRV Home Inspection Services, LLC - Wallingford, CT
Connecticut Home Inspector

Charlie, Or salt and pepper.

Mike, The terminal bar is bonded to the panel.

Mar 12, 2009 08:15 AM #8
Ambassador
1,333,380
Charles Buell
Charles Buell Inspections Inc. - Seattle, WA
Seattle Home Inspector

How could I forget salt and pepper----smack me side the head!

Mar 12, 2009 08:20 AM #9
Rainmaker
67,128
Kevin Corsa
H.I.S. Home Inspections (Summit, Stark Counties) - Canton, OH
H.I.S. Home Inspections, Stark & Summit County, OH Home Inspector

Around here (Ohio) I think Maybe.. one in 10 electric panels are wired 100% correctly. The other nine had Nutsy's relatives squirelling around in them.

Mar 12, 2009 11:10 PM #10
Rainmaker
179,891
Jack Gilleland
Home Inspection and Investor Services, Clayton - Clayton, OH

One thing about it once one of Nutsy's relatives goes in they very rarely come out.

Jim, does each condo pay their own electric?

Mar 13, 2009 06:17 AM #11
Rainmaker
683,909
James Quarello
JRV Home Inspection Services, LLC - Wallingford, CT
Connecticut Home Inspector

Kevin, Same here. I just finished a house that had I think it was 7 separate panels. Everyone had problems.

Jack, That's for sure. I have found my share of mummified rodents in electric panels. Yes the condo owners are responsible to pay their own electric.

Mar 13, 2009 01:36 PM #12
Rainmaker
76,167
Frank Torre
Torre Inspection Service, LLC 888-202-8869 - Hicksville, NY

Hi: James I across this in a panel box that was tap into the main any idea that this is?

Mar 13, 2009 03:58 PM #13
Rainmaker
683,909
James Quarello
JRV Home Inspection Services, LLC - Wallingford, CT
Connecticut Home Inspector

Hi Frank, Looks like it may be some type of surge supressor.

Your pictures are too large. You need to resize them. Please shrink them down.

Mar 14, 2009 02:28 AM #14
Rainmaker
76,167
Frank Torre
Torre Inspection Service, LLC 888-202-8869 - Hicksville, NY

Hi James, I resized the pictures down if you want I will delete them off your blog sorry about the size I did not know you could resize pictures. Thanks Frank

Mar 14, 2009 01:23 PM #15
Rainmaker
683,909
James Quarello
JRV Home Inspection Services, LLC - Wallingford, CT
Connecticut Home Inspector

Frank, That's much better. I don't want to delete them, but when they're full size they over take the page. I saw that same thing the other day on an inspection.

Mar 15, 2009 12:22 AM #16
Rainer
86,824
Mike (Inspector Mike) Parks
The Parks Consulting Group, LLC - Circleville, OH
Inspector Mike

First this cannot be installed on the 'line' side. It must be installed on the 'load' side.

Also notice the threads for attaching it to the outside of the panel.

Without seeing the manf. specs. I would guess that it would be installed on a 220 breaker.

http://www.lightningrodparts.com/instructions.html

Mar 16, 2009 10:35 PM #17
Rainmaker
683,909
James Quarello
JRV Home Inspection Services, LLC - Wallingford, CT
Connecticut Home Inspector

Mike, Thanks for the explanation and the link. I can not ever recall seeing one installed like you described. Makes you wonder who's putting these things in the panel.

Mar 17, 2009 02:08 AM #18
Rainmaker
1,244,485
Steven L. Smith
King of the House Home Inspection, Inc. - Bellingham, WA
Bellingham WA Home Inspector

Mr James,

Happy St Patrick's day to you and I look forward to the big barbecue in July. My family is so excited.

Nutsy

Mar 17, 2009 12:00 PM #19
Rainmaker
507,811
Robert L. Brown
www.mrbrownsellsgr.com - Grand Rapids, MI
Grand Rapids Real Estate Bellabay Realty, West Mic

I understand it enough to be dangerous. Keep up the good work.

Dec 10, 2009 02:26 AM #20
Rainmaker
683,909
James Quarello
JRV Home Inspection Services, LLC - Wallingford, CT
Connecticut Home Inspector

Robert, Thanks. I will try and do my best.

Dec 10, 2009 07:37 AM #21
Rainmaker
507,811
Robert L. Brown
www.mrbrownsellsgr.com - Grand Rapids, MI
Grand Rapids Real Estate Bellabay Realty, West Mic

I've been seeing lots of bad panels here in Michigan. Lots of them have to be replaced after i have them inspected.

Apr 16, 2010 01:43 PM #22
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James Quarello

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