MAIN DIST. PANEL /SERVICE ENTRANCE

1200 AMP SERVICE, PRINT IS TELLING ME TO RUN 4 SETS OF 750 ALUMINUM. NOW I KNOW ITS OVER KILL SOME WHAT, THE ISSUE I AM HAVING, WHEN I INSTALLED THE INTERIOR WITH THE MAIN BREAKER I NOTICED FOR EACH PHASE ONLY 3 PLACES ON EACH PHASE, SO THINGS NOT ADDING UP. HERES A PICTURE OF PANEL TYPE. THANKYOU


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roger

Moderator
Staff member
Location
Fl
Occupation
Electrician
The breaker should have been ordered with provisions for the 4 conductors, if that was not an option it should have been caught during the submittal process. If the manufacturer offers a four lug version it can be changed now, but they may want additional money.

BTW, please turn off your cap lock.

Roger
 

GeorgeB

ElectroHydraulics engineer (retired)
Location
Greenville SC
Occupation
Retired
I was going to be sarcastic and say get the 4 port connectors .... but went to the Eaton website and see they don't offer past 3. BUT, a larger problem for you is that it is rated for copper conductors only. SO ... a junction box for your aluminum conductors to terminate on a 7 position lug suitable for both, then 3 copper to the MCP ... if I read correctly .... but don't miss that you are restricted to tested matching devices with a MCP.
 
OK, I have not ordered the wire yet, could you if I absolutely had to use 7 position lugs inside the mdp.I haven't presented this issue to my boss yet, I just received the interior this past Friday and noticed the problem. There not dual connection, its to small, its made for 3 sets of copper. I'm trying to think of the best solution, and also the cheapest. I can pull three sets of 600 copper, and just have one spare 4 inch conduit, who does the mistake lye with, that's above my pay grade,

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I was going to be sarcastic and say get the 4 port connectors .... but went to the Eaton website and see they don't offer past 3. BUT, a larger problem for you is that it is rated for copper conductors only. SO ... a junction box for your aluminum conductors to terminate on a 7 position lug suitable for both, then 3 copper to the MCP ... if I read correctly .... but don't miss that you are restricted to tested matching devices with a MCP.
According to the Eaton document I saw, there is a 4 port lug, but it only goes up to 500. The 3X750 lugs I saw are dual rated Cu/AL.
https://www.eaton.com/ecm/groups/public/@pub/@electrical/documents/content/il01209005e.pdf page 5.

IT looks like either transition to the appropriate size and quantity(I dont want to know how much those connectors cost) or replace the conductors from the next upstream point with 3X copper or get new lugs and use 4XAl.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
If you're willing to go with 3 sets of 600 kcmil copper (420 * 3=1260 amps) why not just go with 3 sets of 750 aluminum (435 * 3=1305 amps)?
 
I know what the rating is for 750 aluminum, I don't understand why the engineer is calling for 4 sets of 750 al.I brought this up and he started talking about a demand factor for the power company.


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Cow

Senior Member
Location
Eastern Oregon
I'm with the rest of the group, I'm not sure why you're using 4 sets of 750mcm, but if the engineer is hung up on it, I'd consider using pin adapters with those 4 port 500 lugs. You'll have to physically make sure you have the room for all those cables with pin adapters though.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Sometimes you can replace the mechanical lug with crimp on lugs.

Also, as I understand the rules you can use listed lugs to replace the factory supplied lugs. However, listed lugs are often not the right dimensions for the breakers.

There are also some breakers that you can buy an adapter doihickey for that gives you a tongue to attach different lugs to.

Personally I would see if I could make the pin adaptors work BUT I am not sure any of them that are for 750 mcm are listed.
 
OK, the pin adapters, what exactly are they, do they attach to the main breaker, or to the 750al.then the copper to the 3 Port breaker ,sorry I've never used them before.

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OK, I know exactly what they are, do they make a adapter where I can put two 750 al in it, and then take it to the breaker, then just land the others under the other lugs on the main breaker

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roger

Moderator
Staff member
Location
Fl
Occupation
Electrician
If the engineer specified the gear send the problem back to him for a solution.

Roger
 
who does the mistake lye with, that's above my pay grade,

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IT depends. If someone else designed it and specified the gear, then it is their fault. If someone else designed it but you were responsible for procuring the appropriate gear, then I would say it is your responsability. If it is the former, I would not be paying for the time and parts to fix it. I also agree with Roger and let the designer come up with a solution. IF he is dumb enough to use 4 sets of 750 and not confirm terminations, than who knows what he will say of your solution.
 
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