Overcurrent protection over 800 amp for services

J

jap

Senior Member
Occupation
Electrician
infinity said:
I doubt it but maybe it is, I don't know. Regardless that point is moot since in this installation the equipment on the other end is only rated for 75° C.
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And what limits the service equipment to 75d C ?

JAP>
 
J

jap

Senior Member
Occupation
Electrician
So no service equipment is 90d C rated even if it's a bussed structure from the breaker to a connection point with no mechanical terminal lugs?

JAP>
 
J

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
PE (Retired) - Power Systems
jap said:
So no service equipment is 90d C rated even if it's a bussed structure from the breaker to a connection point with no mechanical terminal lugs?

JAP>
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No quite true, but for most applications yes.

Draw out style switchgear, what we used to call ANSI rated, is available with bussed terminations rated at 90°C. The terminations are located in rear compartments of the typically 96" deep enclosures.
 
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don_resqcapt19

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
jap said:
Is a crimpon lug bolted to a transformer spade or bussbar a 75d connection?

JAP>
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Most all compression lugs are rated at least 90°C, but that does not change the equipment rating. You still have to look at that.
 
kwired

kwired

Electron manager
Location
NE Nebraska
As Augie brought up earlier, if you have six disconnecting means you might be able to have less than 1200 amp conductor, still needs to be greater or equal ampacity as calculated load. Six disconnect rule didn't go away in 2020 NEC but they need to be in separate enclosures or separate switchboard sections.
 
don_resqcapt19

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
kwired said:
As Augie brought up earlier, if you have six disconnecting means you might be able to have less than 1200 amp conductor, still needs to be greater or equal ampacity as calculated load. Six disconnect rule didn't go away in 2020 NEC but they need to be in separate enclosures or separate switchboard sections.
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You just add a 30 amp service disconnect along side the 1200 amp one and then your conductors only need to be equal to the calculated load.
 
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