Pole Building -- Electrical Question

[dcyrilc]

Yes, things change but the way things were wired using 3 wires and a grounding rod is safe and grandfathered in so I would not lose any sleep over it.

Chris

Another reason for the code change has to do with too many electricians and inspectors who do not properly understand grounding. Many systems were built and approved even though not properly (safely) constructed because of improper bonding of 3 wire and 4 wire systems. By eliminating the option, it now must be built to a single standard and no mixup should be possible.

Another misnomer has to do with ground rods. Ground rods DO NOT provide short circuit or overload protection! Gound rods provide protection from transient voltages within an electrical system. You can hook a #12 wire with a 20 amp breaker directly to a ground rod without tripping! Ohms law on a 25 ohm ground rod (code requirement) is under 20 amp of curent flow, no short circuit! This is why the ground and neutral must be bonded on three wire systems. Note, the feed from the power company is a three wire system. Bond neutral and ground for short circuit/overload protection.

 

[dcyrilc]

Jim, if you have an existing 3 wire feed to a separate building, yes bond the neutral to the cabinet and make sure there is a ground rod installed. It's the best you can do at this point.
The NEC was changed because the old arrangement was causing current to be carried on the neutral conductor in a fault to ground situation. The ground rod does not make a "ground". It is just a method of bleeding off transient voltage, such as lightning. The earth is a poor conductor for a fault to ground to return to it's supply and will not be a low impedance path back to to the supply. The neutral conductor then must try to be that low impedance path.

My hat is off to you sir. As a 30 year liscensed electrician, I have been amazed over the years at how many inspectors (and electricians) did not understand the principles grounding and bonding. The people in your area are lucky to have someone who understands this element of safety.

 

[dcyrilc]

ATTENTION EVERYONE: I Got it!!!!!!!!!! Cyril, When you come down from your high horse just understand that not everyone knows everything. This is why people on this forum ask questions. The way I understand it, the code prohibiting a 3 wire system was only changed in 2008. So lets not pretend that this has never been an accepted method. Hopefully this will put the issue of 3 and 4 wire subpanels to rest. I appreciate your knowledge but lets not belittle someone for not being as in the know as you might be in the electrical field. Love and Kisses, Jim

Jim,
If you felt belittled by me, then I appoligize for that was not my intent. My intent was to try to clarify the difference between three wire and four wire systems and help to explain the necessity for how each is wired so that it would be a safe system. It was was not intended as critism of anyone.

As for the 2008 code change, I for one have been disapointed by this change, as I prefer the three wire system and have six outbuildings across my 17 acres wired as three wire subpanels.

The three wire system is better for longer runs in my opinion. Four wire systems are great for short runs, but can create issues for providing short circuit protection on long runs due to line loss and inherent resistance in the wire.

Anyway, again I appoligize if you felt that I had critisized you. I applaude anyone who desires to learn and know more about the things they are involved in with their lives. I complimented Inspector507 on this, since the principles of bonding and grounding are not well understood within the electrical industry and from reading his posts believe that he works within this industry.

I hope that this softens any hurt feelings between us. I have the utmost of admiration for you Sir.

 

[LD1]

All this confusion about three wire and 4 wire and ground rods has got me wondering wether my set-up is "ok". Those of you in the electrical field please confirm if it is "up to code" or not.

I have 3-wire direct burry triplex 200A to the house. Neutral is bonded and the ground rod is connected with a 8 ga copper wire.

From the house I installed a 100A breaker and ran 60ft of direct burry triplex to the 100A main breaker of the pannel in the garage. Neutral is bonded there to but no ground rod.

Should there be a ground rod at the garage?? Bonded neutral of not??

This is how I have seen many buildings wired, including 3 @ my parents and have never had any problems.

 

[dcyrilc]

All this confusion about three wire and 4 wire and ground rods has got me wondering wether my set-up is "ok". Those of you in the electrical field please confirm if it is "up to code" or not.

I have 3-wire direct burry triplex 200A to the house. Neutral is bonded and the ground rod is connected with a 8 ga copper wire.

From the house I installed a 100A breaker and ran 60ft of direct burry triplex to the 100A main breaker of the pannel in the garage. Neutral is bonded there to but no ground rod.

Should there be a ground rod at the garage?? Bonded neutral of not??

This is how I have seen many buildings wired, including 3 @ my parents and have never had any problems.

With the 3 wire system, the sub-panel is treated as a main panel. This means bond the neutral and ground at the sub-panel and install a ground rod. The ground rod is not as critical as the bonding, but is still a good idea. Bonding the neutral and ground at the panel is critical for short circuit protection or more accurately, ground fault protection.

In short, yes the neutral and ground should be bonded, and yes there should be a ground rod.

 

[Inspector507]

I've been going through my NEC book (1993 edition) and I can't seem to find the answer. Thanks in advance, Jim

Jim here's your answer. The 1993 NEC also required a 3 wire system to have a ground rod installed.

 

[Inspector507]

My hat is off to you sir. As a 30 year liscensed electrician, I have been amazed over the years at how many inspectors (and electricians) did not understand the principles grounding and bonding. The people in your area are lucky to have someone who understands this element of safety.

Learning and understanding that element and everything else in the NEC is what allows me to eat. It's been my living for more than 20 years as an inspector.

 

[firefighter jim]

Jim,
If you felt belittled by me, then I appoligize for that was not my intent. My intent was to try to clarify the difference between three wire and four wire systems and help to explain the necessity for how each is wired so that it would be a safe system. It was was not intended as critism of anyone.

As for the 2008 code change, I for one have been disapointed by this change, as I prefer the three wire system and have six outbuildings across my 17 acres wired as three wire subpanels.

The three wire system is better for longer runs in my opinion. Four wire systems are great for short runs, but can create issues for providing short circuit protection on long runs due to line loss and inherent resistance in the wire.

Anyway, again I appoligize if you felt that I had critisized you. I applaude anyone who desires to learn and know more about the things they are involved in with their lives. I complimented Inspector507 on this, since the principles of bonding and grounding are not well understood within the electrical industry and from reading his posts believe that he works within this industry.

I hope that this softens any hurt feelings between us. I have the utmost of admiration for you Sir.

Apologies on my behalf also Cyril. No hard feelings. Jim

 

[buckeyefarmer]

Paul and any other person in the know, I did NOT bond the neutral in the subpanel of my outbuilding that I fed with the 3 wire system a couple years ago. Should I leave it that way? I'm hearing conflicting stories (to bond or not to bond subpanels with 3 wire supplies). I've been going through my NEC book (1993 edition) and I can't seem to find the answer. Thanks in advance, Jim

In the 1996 code it is 250-24, can't find my 93 code book at the moment but should be in that area. Exception 2 says you don't bond if you pull the 4th wire (Equipment Ground).

A 3 wire to another building was as if you were coming off a transformer (but you weren't). This works ok if there are no other paths for grounds to connect back to the source panel, but once you run a phone line or cable tv or cat 5, etc.., you have put in a path and that makes the 3 wire setup unsafe.

 

[dcyrilc]

In the 1996 code it is 250-24, can't find my 93 code book at the moment but should be in that area. Exception 2 says you don't bond if you pull the 4th wire (Equipment Ground).

A 3 wire to another building was as if you were coming off a transformer (but you weren't). This works ok if there are no other paths for grounds to connect back to the source panel, but once you run a phone line or cable tv or cat 5, etc.., you have put in a path and that makes the 3 wire setup unsafe.

I cheated on the communication and video between my out buildings... I used fiber optics. Nonconductive.

 

[eepete]

I cheated on the communication and video between my out buildings... I used fiber optics. Nonconductive.

What did you put in? Pointer to fiber and electronics would be great, tnx.

Pete

 

[dcyrilc]

What did you put in? Pointer to fiber and electronics would be great, tnx.

Pete

I'm using International Fiber Systems (IFS) VT1910/VR1910 video convertors with 2 way data for my security cameras and a combonation of Cysco Systems and IFS switches for internet/intranet communications over fiber. Retail price for my security system would be pushing $200K. Between Ebay and other sources, I'm into it about $15K. I lost over $20K worth of items over three years before I resorted to building and installing this system. Currently, one thief caught. He was dumb enough to park his work van directly in front of video surveilance sign on the front gate. I have three cameras viewing this location. One of which, is a .001 lux high res fixed camera with a 30:1 zoom looking straight out the gate from 200 ft up the drive. As soon as he turned off the headlights, I had a perfect recording of the liscense plate. My field of view with that camera at the gate is about 8ft wide centered on the 12ft gate. I have a fixed area view camera also to record activity in that area and a pan/tilt camera also recording the area. As I don't live on the property, I have a VPN connection to my house allowing me live access to the cameras for viewing and control and well as access to the recorded images. I use a Pelco DX8016 DVR (about $8K new) for recording and can hold about a weeks worth of video for 16 cameras on the hard drive. All video is watermarked, making it usable in court as evidence.

I'm currently looking for an alarm panel which will use IP protocol for communication with sub-panels in remote buildings (haven't found one that I am satisfied with yet). Once I have that resolved, I can use alarm triggers to turn cameras to preprogrammed locations for recording building entry violations. I have people break into my property, on average, once to twice a year. I got tired of it. I put in the system I did, because IMO, if I cannot positively identify a face and a plate, the system has little to no value. People out here obviously do not believe that the signs are real.

 

[woodlandfarms]

So Cyril, are you loosing copper to the tweakers or is this something more.

My video system set me back about $400 for 4 cameras, but none move, and I have to use webrowser. to view the respective house. No detail on any of the cameras, but the one guy we caught was working for a contractor whom was on the property. Easy find.

Carl

 

[dcyrilc]

So Cyril, are you loosing copper to the tweakers or is this something more.

My video system set me back about $400 for 4 cameras, but none move, and I have to use webrowser. to view the respective house. No detail on any of the cameras, but the one guy we caught was working for a contractor whom was on the property. Easy find.

Carl

The last large theft was of 10 used 14ft aluminum street light poles which I had spent two years talking one of the local cities out of. Policies have since changed in this area and laws require used/surplus items to be recycled now days. Replacement cost for those poles new was $9K as used replacements were no longer available. Previous to that, when we thought we were going to be able to put a house on the property, we sold our house and were living with my mother and had all our personal property stored on our land in the moble home we had purchased through a bank repo. Someone kicked in the doors and stole most of the things we had which had any value, crystal, silverware, leather sectional, my wife's teddy bear collection, etc. I've had copper cable stolen out of the ground as well as reels stolen which were being stored in buildings for use on jobsites. We have had building broken into and tools stolen. The last time they broke into the building, they removed the screws fron the steel siding and pulled it back to pull out the insulation and kick in the sheet rock for entry. The problems started about 10 years ago. Previous to that we never had a problem. We have had locks cut on the gates and we have had the chain link cut to the side of the gate. The hardest part has been trying to determine the best locations for the cameras and where to have them looking.

I've purchased many of my cameras off Ebay and rebuilt them from being nonfunctional into functional cameras. The 30:1 Pelco zoom lens I bought lists at about $2400 and I bought for $50. It cost me about $45 to ship it to Pelco and have the focus and zoom servos replaced. My most expensive PTZ setup lists at $4200 and I think I have about $650 into it. One of my purchases for fiber equipment was $300 for 41 pieces of various transmitters and receivers. I use IFS equipment because IFS has a lifetime warrenty and doesn't care that I bought them off Ebay. It's also high quality equipment.

The person we caught worked for a contractor in a neighboring city (Mercer Island). The Ford van he was driving belonged to his boss. I doubt his boss was happy when the detectives showed up with the videos and asked who had the van that night!

 

[SOS]

Well my building will only be 250 feet from the house so I'm planning on dropping a couple of cat 5s for my network and cctv. I'm pretty sure they work upto 350 feet without a repeater.

 

[SOS]

Where does your electrical service come into your property relative to where you are planning this building?

In my case, the supply came up from the road roughly following the drive to house. When I had an existing pole barn and a new metal horse barn wired we excavated and tied into the supply line under ground* near the project. My electrician was concerned that if we came from the house and back to the new service there would be capacity problems. It also saved material and was a lot simpler job. He earned his money with me right there.


*The connection was made in a Traffic box.

The transformer is about 500 to 600 feet away on the otherside of the property. see pic.

 

[dcyrilc]

Well my building will only be 250 feet from the house so I'm planning on dropping a couple of cat 5s for my network and cctv. I'm pretty sure they work upto 350 feet without a repeater.

The accepted maximum distance for Cat-5 is 100 meters (325 feet) so you should be fine.

 

[firefighter jim]

Jim here's your answer. The 1993 NEC also required a 3 wire system to have a ground rod installed.

Thanks again 507 and Cyril..............Happy New Year to you both. Jim

 

[dcyrilc]

Thanks again 507 and Cyril..............Happy New Year to you both. Jim

Happy New Year Jim.

What is the picture in your avitar? I can't quite make it out, but it looks cool!

 

[firefighter jim]

Happy New Year Jim.

What is the picture in your avitar? I can't quite make it out, but it looks cool!

Model T Ford which had a rather unfortunate accident in Washington D.C. (1922)!