Garage recep. 2014 NEC

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Smart $ said:
In that case you'd need a separate branch circuit, and the GDO receptacle would not count... but evaluating from a strict HP to watts conversion, it would have to be a 1.2HP GDO. :blink:
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But NEC load calculations are based on VA not watts, so it needs to have high power factor and high efficiency.
 
kwired said:
They don't specify watts either, but do specify volts as well as amps - do the math:p
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Well I don't have one handy, and I was looking at sales-type web sites for the info. All that is moot anyway. If the unit has a labeled HP, have to use values from Table 430.248... which puts 1/2HP and up over the limit of a 15A circuit. On a 20A circuit, a 1/2HP GDO would not be over the limit.
 
Smart $ said:
... A quick check of product power requirements noted on shopping websites only have 1/2 and 3/4 HP GDO's drawing 60 to 120 watts
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No question - they are lying. They probably use the same people that write the sears aircompressor ads.

edit to add example:
Say a residential spring balanced door weighs 30 lbs, raises 8 feet in 10 seconds. Thats 24 (lb-ft)/sec. Double that for parasitic drag. That's about 50 (lb-ft)/sec. That is less than a 1/10 of a HP - Which is more in line with the 60 - 120 watts. Nowhere near 1/2 - 3/4 HP.

Yep - they lie.

ice
 
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iceworm said:
No question - they are lying. They probably use the same people that write the sears aircompressor ads.

edit to add example:
Say a residential spring balanced door weighs 30 lbs, raises 8 feet in 10 seconds. Thats 24 (lb-ft)/sec. Double that for parasitic drag. That's about 50 (lb-ft)/sec. That is less than a 1/10 of a HP - Which is more in line with the 60 - 120 watts. Nowhere near 1/2 - 3/4 HP.

Yep - they lie.

ice
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Yes they may... but they may not. Have to remember the motor may not be running at full load at the conditions stated. They also may have the overload set low... so a bind or other impediment doesn't actually overload the motor as we normally perceive a motor overload.
 
Smart $ said:
Yes they may... but they may not. (be lying).
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Well, you did find the information on the internet - so it is likey true:roll:

Then again:
The motor on my air compressor is an industrial grade (cheap industrial grade) 3/4hp. It is about 8 inches in Dia and 12 inches long.

The motor on my GD opener is about 5" Dia and 7" long. That's about a fourth the copper and steel as the AC motor. Which do you supose is closer to 3/4 hp?

ice
 
iceworm said:
Well, you did find the information on the internet - so it is likey true:roll:

Then again:
The motor on my air compressor is an industrial grade (cheap industrial grade) 3/4hp. It is about 8 inches in Dia and 12 inches long.

The motor on my GD opener is about 5" Dia and 7" long. That's about a fourth the copper and steel as the AC motor. Which do you supose is closer to 3/4 hp?

ice
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Is this a test? :angel:
 
My guess is any residential GDO marked 3/4 HP can likely develop 3/4 output - but only for limited time period and not continuously.

The big letters on the side of the unit are not the nameplate - chances are the nameplate only says volts and amps but not HP.

Besides it comes with a 5-15 cord cap - so apparently is intended to work on a 15 amp circuit.
 
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Future use

Future use

Just an aside, but...the reason for these receptacles may be a future need for electric car charging. Marin County California, (See Lenny Bruce's comment, "Marin County, Sintown USA"), or it might be just the city of Tiburon, now requires a car charging receptacle in the garage on all new construction.
 
Pierce said:
Just an aside, but...the reason for these receptacles may be a future need for electric car charging. Marin County California, (See Lenny Bruce's comment, "Marin County, Sintown USA"), or it might be just the city of Tiburon, now requires a car charging receptacle in the garage on all new construction.
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I think it likely is the reason, but also think it may be too soon to make such a requirement. AFAIK not all EV chargers have 15 amp 120 volt plug on them, but NEC is suggesting we need at least one 15 amp 120 volt circuit to accommodate such equipment. Some people will have higher capacity charging equipment and will not necessarily need such a circuit, others may need more then one circuit whether 15/120 or not. Some will not need to charge EV's at all - at least for quite some time.
 
Pierce said:
Marin County California, (See Lenny Bruce's comment, "Marin County, Sintown USA"), or it might be just the city of Tiburon, now requires a car charging receptacle in the garage on all new construction.
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That is SO premature. IF (a big if) I wanted to be prepared for electric cars, and if it were in the purview of the NEC, I would strongly consider requiring a 3/4 conduit from a panel (suitable for 50 additional amps per stall with some multi-unit factor) to each stall. That's what I would specify in a new home for me if I lived in Kalifornia.

Can any electric car (I don't mean golf cars or hybrids) realistically be charged from a 20A 120V circuit?
 
GeorgeB said:
That is SO premature. IF (a big if) I wanted to be prepared for electric cars, and if it were in the purview of the NEC, I would strongly consider requiring a 3/4 conduit from a panel (suitable for 50 additional amps per stall with some multi-unit factor) to each stall. That's what I would specify in a new home for me if I lived in Kalifornia.

Can any electric car (I don't mean golf cars or hybrids) realistically be charged from a 20A 120V circuit?
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That depends on how much charge and in what kind of time you call realistic.
 
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