A/C recptacle and baseboard heat circuits

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mbrooke

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Situation where a group of apartments have both electric baseboard heat, and A/C through the wall units. The A/C outlets happen to be tapped off the baseboard heat circuits. The circuits are 20 amps feeding both the floor base boards and a NEMA 6-20 for the wall units.


So far I cant find anything specific in the NEC; but this cant be technically right, correct?
 

electricman2

Senior Member
Location
North Carolina
Occupation
Retired Electrical Contractor
Would not the baseboard heater load be limited to 50% of 20A because of 210.23(A)(2) since the circuit also supplies the A/C receptacle? Just asking
 

GoldDigger

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Placerville, CA, USA
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Retired PV System Designer
I would say so, since the NEC does not recognize the fact that the two uses are mutually exclusive, since there is no control over what you plug into the receptacle(s).
If the A/C units were hard wired, could either one use either 80% or 100% of the circuit capacity, and you would just trip the breaker if you decided to run both at once?

Tapatalk!
 

iwire

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Staff member
Location
Massachusetts
Would not the baseboard heater load be limited to 50% of 20A because of 210.23(A)(2) since the circuit also supplies the A/C receptacle? Just asking

In my opinion that section does not apply because the both the heaters and the AC units are fastened in place.



210.23(A)(2) Utilization Equipment Fastened in Place. The total
rating of utilization equipment fastened in place, other than
luminaires, shall not exceed 50 percent of the branchcircuit
ampere rating where lighting units, cord-and-plugconnected
utilization equipment not fastened
in place, or
both, are also supplied.


I would say so, since the NEC does not recognize the fact that the two uses are mutually exclusive, since there is no control over what you plug into the receptacle(s).

Its going to be tough plugging the vacuum into the 240 volt outlet.
 

mbrooke

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Location
United States
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Technician
Ok guess Im not the only one not seeing anything prohibiting it.


I still wondering since the window A/C are cord and plug connected if loading rules apply since the heaters are hard wired. Its been my assumption that if a cord and plug connected device are involved fixed in place equipment cant go over 50%. The baseboards on average seem to tally up about 70% to 80% of the circuits rating with all of them running on any circuit.


"210.23(A)(2) Utilization Equipment Fastened in Place. The total
rating of utilization equipment fastened in place, other than
luminaires, shall not exceed 50 percent of the branchcircuit
ampere rating where lighting units, cord-and-plugconnected
utilization equipment not fastened
in place, or
both, are also supplied."


From the looks of it boils down to how the A/C unit is mounted?:huh:
 

fmtjfw

Senior Member
Unless you are a crazy person like me with several German appliances, you are unlikely to use 250V 15/20A receptacles in you home for other than air conditioning. The idea of sharing 20A circuits between A/C and electric heating makes a lot of sense. They are not on at the same time (barring idiotic behavior). By placing them on the same breaker the load calculation assuming only one load at time is enforced by the CB.

What's not to like?
 

mbrooke

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Technician
Unless you are a crazy person like me with several German appliances, you are unlikely to use 250V 15/20A receptacles in you home for other than air conditioning. The idea of sharing 20A circuits between A/C and electric heating makes a lot of sense. They are not on at the same time (barring idiotic behavior). By placing them on the same breaker the load calculation assuming only one load at time is enforced by the CB.

What's not to like?


I agree. From a load perspective its entirely possible, and it saves copper. Good to know the NEC agrees too:D
 

iwire

Moderator
Staff member
Location
Massachusetts
Unless you are a crazy person like me with several German appliances, you are unlikely to use 250V 15/20A receptacles in you home for other than air conditioning.

Unless those appliances are over 1440 VA that is a violation on it's own. :D 210.6(A)(2)
 

kwired

Electron manager
Location
NE Nebraska
Unless you are a crazy person like me with several German appliances, you are unlikely to use 250V 15/20A receptacles in you home for other than air conditioning. The idea of sharing 20A circuits between A/C and electric heating makes a lot of sense. They are not on at the same time (barring idiotic behavior). By placing them on the same breaker the load calculation assuming only one load at time is enforced by the CB.

What's not to like?
and if for some reason you had both the AC and heat running in the same space it maybe isn't all that bad to have the breaker trip in that circumstance. Just how does NEC comply with it's own 90.1 by requiring separate circuits here? Or many other sections and 90.1 for that matter?
 

mbrooke

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Location
United States
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Technician
and if for some reason you had both the AC and heat running in the same space it maybe isn't all that bad to have the breaker trip in that circumstance. Just how does NEC comply with it's own 90.1 by requiring separate circuits here? Or many other sections and 90.1 for that matter?


That's what Im wondering. The section iwire posted says the devices must be mobile rather than fixed in place.

As long as the occupant isn't careless, its an elegant way of saving copper, but knowing the NEC Im still slightly thinking otherwise.
 

iwire

Moderator
Staff member
Location
Massachusetts
, its an elegant way of saving copper, but knowing the NEC Im still slightly thinking otherwise.

I think sadly at one time the NFPA used restraint in rule making. If there was no clear safety hazard it was allowed.

Now in the name of product sales and the change in the nation from 'be responsible for yourself' to 'everyone needs a nanny' results in a much different NFPA.
 

mbrooke

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Location
United States
Occupation
Technician
I think sadly at one time the NFPA used restraint in rule making. If there was no clear safety hazard it was allowed.

Now in the name of product sales and the change in the nation from 'be responsible for yourself' to 'everyone needs a nanny' results in a much different NFPA.


I think I can agree with you 100% on that. I see the NEC going from common sense safety to both a design manual and marketing platform. That's not progress:happyno::rant:
 

kwired

Electron manager
Location
NE Nebraska
I think I can agree with you 100% on that. I see the NEC going from common sense safety to both a design manual and marketing platform. That's not progress:happyno::rant:
Then they need to change 90.1 so they are not contradicting themselves:happyyes:
 

iwire

Moderator
Staff member
Location
Massachusetts
Then they need to change 90.1 so they are not contradicting themselves:happyyes:

Reorganize 90.1 and add new section under (B).


90.1 Purpose.

(A) Practical Safeguarding.
The purpose of this Code is
the practical safeguarding of persons and property from
hazards arising from the use of electricity.

(B) Safety net This code contains provisions that are considered comforting for the untrained and sales for the manufacturers that cannot sell their product without help.

Informational Note: Hazards often occur because professionals assume that people who work on electrical equipment will be qualified. As it turns out this is untrue, it is up to all of us to pull together and make sure the untrained cannot be hurt or held responsible for their own actions. Also CEOs of failing companies have trouble making the payments on their forth vacation home. This is a travesty that the NEC is addressing by adding code sections requiring new, unavailable, unproven equipment, concepts and methods without adding to the overall safety of the electrical system.



(C) Adequacy. This Code contains provisions that are considered
necessary for safety. Compliance therewith and
proper maintenance results in an installation that is essentially
free from hazard but not necessarily efficient, convenient,
or adequate for good service or future expansion of
electrical use.

Informational Note: Hazards often occur because of overloading
of wiring systems by methods or usage not in conformity
with this Code. This occurs because initial wiring
did not provide for increases in the use of electricity. An
initial adequate installation and reasonable provisions for
system changes provide for future increases in the use of
electricity.


(D) Intention. This Code is not intended as a design specification
or an instruction manual for untrained persons.

(E) Relation to Other International Standards. The requirements
in this Code address the fundamental principles
of protection for safety contained in Section 131 of International
 
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