Do I need to specify conduit and conductor size for branch ????

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AWinston

Member
Location
Murrieta, Ca
I have a client that is asking if I can specify the conduit and conductor size for every branch circuit. This is a fairly large project and I've only specified conduit and conductor sizing for service conductors and feeders. Is this required? The circuits range from 15A to 50A.
 

ron

Senior Member
Not required by any code, but you can easily call out sample breaker and wire size combinations, then 3/4"C for each circuit. If the contractor wants to combine, and of course they will, they will size the conduit depending on the routing. That makes it easier to avoid the hassle of derating for >ccc since the EC will take that on.
 

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
I suppose it would depend on the project delivery type. If this is a design-bid-build project, then all prospective bidders should be able to base their prices on the same design information. In that case, I would give the branch circuit sizes. If this is a design-build project, then I think you can leave much of that detail to the design arm of the design/build team.

Our standard practice is to state that all 20 amp branch circuits use #12 wire unless shown otherwise. We also include a generic clause to upsize to #10 for 120 volt, 20 amp circuits over 100 feet long. The distance is 200 feet for 20 amp 208 or 277 volt circuits.

For anything that needs a 30 amp or higher branch circuit, we include an electrical connections schedule. It lists everything that appears on the mechanical or plumbing schedule as needing a power source (e.g., supply fans, booster pumps, circulating water pumps, etc.). We show the same HP as they show, and our Excel file calculates the appropriate branch circuit design (i.e., conduit, breaker, and wire sizes). We don't show that information on the floor plans. We only show the component's name (e.g., "CP-1"), and leave it to the contractor to look for that component on the electrical connections schedule.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
I have a client that is asking if I can specify the conduit and conductor size for every branch circuit. This is a fairly large project and I've only specified conduit and conductor sizing for service conductors and feeders. Is this required? The circuits range from 15A to 50A.

It is not required by code. It may be required to get a permit. If the customer is willing to pay for it, what is wrong with giving him what he wants?
 

AWinston

Member
Location
Murrieta, Ca
It is not required by code. It may be required to get a permit. If the customer is willing to pay for it, what is wrong with giving him what he wants?

It just takes more time and effort. This particular client keeps coming back with comments after multiple rounds of review. My initial thought was to charge him additional hours since I really don't have the time.
 

Fitzdrew516

Senior Member
Location
Cincinnati, OH
I usually add a general note that all 20A/15A single pole breakers are to be fed with #12's in 3/4" unless noted otherwise and then I refer them to a max distance table for 20A/15A breakers for voltage drop purposes. About 2/3 of my circuits are 20A/1P or 15A/1P so this helps out a lot. I usually put the other wire sizes in the panel schedules, but if you wanted to develop a whole wire size table you could do that as well. If you go any of these routes it really cleans up the drawings because you don't have to have a keyed note for every circuit which is pretty asinine.

-Drew
 

kwired

Electron manager
Location
NE Nebraska
It just takes more time and effort. This particular client keeps coming back with comments after multiple rounds of review. My initial thought was to charge him additional hours since I really don't have the time.
Nothing wrong with that either. Maybe he will learn how to use a code book if you start to do that.
 

kingpb

Senior Member
Location
SE USA as far as you can go
Occupation
Engineer, Registered
I have a client that is asking if I can specify the conduit and conductor size for every branch circuit. This is a fairly large project and I've only specified conduit and conductor sizing for service conductors and feeders. Is this required? The circuits range from 15A to 50A.

What is required by the Contract? Who is the client you mention; Owner? Why are they asking for this?
 

AWinston

Member
Location
Murrieta, Ca
What is required by the Contract? Who is the client you mention; Owner? Why are they asking for this?

It isn't required by contract. The person asking is the Mechanical firm that hired me who was hired by the architect. They were asking because they say they are concerned that questions may arise from the field. My response is...the field should know how to select wire and conduit size. Once I get some downtime, I'll create a table ranging from 15A-100A for short distances on my general notes page.
 

kingpb

Senior Member
Location
SE USA as far as you can go
Occupation
Engineer, Registered
It isn't required by contract. The person asking is the Mechanical firm that hired me who was hired by the architect. They were asking because they say they are concerned that questions may arise from the field. My response is...the field should know how to select wire and conduit size. Once I get some downtime, I'll create a table ranging from 15A-100A for short distances on my general notes page.

I would provide a ckt list for any mechanical equipment. Then some general notes about branch ckts for lights and receptacles.
 
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