DARUSA
Senior Member
- Location
- New York City
Wich sise of wire I have to use to bond the steel frame of the building for a 7000amps service? I tought # 4 is the m?ximum size Wire required.Is it correct?.
Beam bonding
- Thread starter DARUSA
- Start date
- Status
- Location
- New Jersey
- Occupation
- Journeyman Electrician
If this is the structural steel frame of a building that qualifies as an electrode you'll need to use Table 250.66. It's bigger than #4 which is the maximum required for a CEE.
DARUSA
Senior Member
- Location
- New York City
250.66 is based on the CM of the service entrance wire that means I will have to runn a 3/0 wire.Another question is how can I terminate it to the Beam?
Is it a special connector for that?
Is it a special connector for that?
- Location
- Logan, Utah
You can also use a crimp on lug to the 3/0 wire and bolt the lug onto the beam with a bolt and nut.
Chris
Chris
DARUSA
Senior Member
- Location
- New York City
- Location
- New Jersey
- Occupation
- Journeyman Electrician
That's correct, the largest conductor listed in that table is #3/0 for a GEC to building steel.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- Semi-retired engineer
The most common thing I have actually seen used is a beam clamp. I have always had my doubts about it being code though.
- Location
- Logan, Utah
The problem that I have with beam clamps is the 250.8 requires the means used to attach the GEC to the electrode to be listed for the purpose and I have never seen a beam clamp that is listed for grounding.
Chris
A/A Fuel GTX
Senior Member
- Location
- WI & AZ
- Occupation
- Electrician
What about a mechanical lug bolted to the beam?
brantmacga
Señor Member
- Location
- Georgia
- Occupation
- Former Child
that's how I do it.
That will make three of us !!
- Location
- New Jersey
- Occupation
- Journeyman Electrician
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Oh, what the heck: five! :roll:
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Of course you may use larger than #4 but you are only required to use a gec that is not larger than #4. For a 100 amp service you can use smaller but in no case are you required to run larger than #4.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
According to 250.66(B) the GEC to a CEE "shall not be required to be larger than 4 AWG copper wire." So #4 is the maximum required. You could always use a larger size if so choose.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- Semi-retired engineer
Won't get any argument from me on that one. Just telling you what I have seen used. For some people the extra couple minutes required to drill a hole for a lug is just too much.
- Status