ohm's law sucks.

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iwire

iwire

Moderator
Staff member
Location
Massachusetts
Daniel malack said:
210.19 Conductors ? Minimum Ampacity and Size.
(A) Branch Circuits Not More Than 600 Volts.
FPN No. 4: Conductors for branch circuits as defined inArticle 100, sized to prevent a voltage drop exceeding3 percent at the farthest outlet of power, heating, and lightingloads, or combinations of such loads, and where themaximum total voltage drop on both feeders and branchcircuits to the farthest outlet does not exceed 5 percent,provide reasonable efficiency of operation. See FPN No. 2of 215.2(A)(3) for voltage drop on feeder conductors.

NEC has specified percentages of voltage drop!
Transforming it should be cheaper.
Click to expand...

That is not a requirement, that is an FPN and I am well aware of it.
 
Rampage_Rick

Rampage_Rick

Senior Member
Location
British Columbia, Canada
I'd verify that 7 amps figure... I can't imagine any wireless equipment drawing over 800 watts. The transmitter itself should be a couple watts at the most, and the smarts should only draw around 100W.

We did a wireless mesh network on the golf course. 400+ acres served by 11 towers, which were powered from the irrigation control system. Each tower consists of two Colubris access points (1 dual channel; 3 radios total) and a 1000 mW amplifier mounted on a fiberglass pole in a weatherproof enclosure.

One of the irrigation power circuits feeds 6 towers, plus a dozen Toro irrigation satellites. The circuit capacity is only 20A 120V and I'd estimate the load is 15A. There are also a couple 15A circuits that feed 1-2 towers and 4-5 satellites.
 
Fulthrotl

Fulthrotl

~Autocorrect is My Worst Enema.~
Location
HB, CA (19 Hrs. 22 Min. from Winged Horses)
Occupation
E
Rampage_Rick said:
I'd verify that 7 amps figure... I can't imagine any wireless equipment drawing over 800 watts. The transmitter itself should be a couple watts at the most, and the smarts should only draw around 100W.

We did a wireless mesh network on the golf course. 400+ acres served by 11 towers, which were powered from the irrigation control system. Each tower consists of two Colubris access points (1 dual channel; 3 radios total) and a 1000 mW amplifier mounted on a fiberglass pole in a weatherproof enclosure.

One of the irrigation power circuits feeds 6 towers, plus a dozen Toro irrigation satellites. The circuit capacity is only 20A 120V and I'd estimate the load is 15A. There are also a couple 15A circuits that feed 1-2 towers and 4-5 satellites.
Click to expand...

building is 770' x 1600'.

there are three repeaters, 7 amps. i checked.

i'm setting a subpanel 600' from the main switchgear,
and the plug is 500' from THAT. subpanel is fed by a
15kva xfmr on wall above panel. 480 volt 3 ph feed to
xfmr. 1/0 compact aluminum feeding the xfmr.

it's a wireless pick system with screens on the forklifts.

#6 it is for the branch circuit... it'll all work out. i originally
swagged it as a #10 without bothering to measure.

you have a dumb head, the wallet suffers.

on a positive note, i got 750' of 1 1/2" emt installed 30'
up in the air between 8 am and 12:30. called it a day.
mostly straight, some 4 point saddles, and whatnot, but
it went quick.
 
S

satcom

Senior Member
Fulthrotl said:
building is 770' x 1600'.

there are three repeaters, 7 amps. i checked.

i'm setting a subpanel 600' from the main switchgear,
and the plug is 500' from THAT. subpanel is fed by a
15kva xfmr on wall above panel. 480 volt 3 ph feed to
xfmr. 1/0 compact aluminum feeding the xfmr.

it's a wireless pick system with screens on the forklifts.

#6 it is for the branch circuit... it'll all work out. i originally
swagged it as a #10 without bothering to measure.

you have a dumb head, the wallet suffers.

on a positive note, i got 750' of 1 1/2" emt installed 30'
up in the air between 8 am and 12:30. called it a day.
mostly straight, some 4 point saddles, and whatnot, but
it went quick.
Click to expand...

You have a nice project, the wide band repeater installations for distributions for the mobile pick systems do use more power, then home, and small office repeaters.
 
Fulthrotl

Fulthrotl

~Autocorrect is My Worst Enema.~
Location
HB, CA (19 Hrs. 22 Min. from Winged Horses)
Occupation
E
hardworkingstiff said:
Did we ever hear what size wire the plans call for?
Most jobs I've bid tell you the wire size somewhere.
Click to expand...

the prints will call for two #6 and #8 ground.

i haven't drawn them yet.

it was my shortfall, i didn't realize the repeaters would pull that much.
i was figuring a nominal 180 watts per device, a quad would give 360 watts, or three amps.

i am now the proud owner of six rolls of #6 simpull, and three rolls of #8 green simpull.
$2,200 or so.

next time, i'll clarify something like that.... 'eh, it's only THREE OUTLETS, not even something to consider.... ;-)
 
kwired

kwired

Electron manager
Location
NE Nebraska
Fulthrotl said:
the prints will call for two #6 and #8 ground.
Click to expand...

If this is a 20 amp circuit and conductor size is increased to #6 for voltage drop purposes then the equipment grounding conductor also needs to be increased to #6.

If this is a 60 amp circuit using 6 AWG conductors - the equipment grounding conductor can be 10 AWG.

Just doesn't quite sound right does it? But that is what code says.

A code compliant way to use the 10 AWG EGC is to run a feeder to near the outlet with 10AWG EGC. Then run shorter 20 amp branch circuit to the outlet with smaller conductors.
 
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T

texie

Senior Member
Location
Fort Collins, Colorado
Occupation
Electrician, Contractor, Inspector
kwired said:
If this is a 20 amp circuit and conductor size is increased to #6 for voltage drop purposes then the equipment grounding conductor also needs to be increased to #6.

If this is a 60 amp circuit using 6 AWG conductors - the equipment grounding conductor can be 10 AWG.

Just doesn't quite sound right does it? But that is what code says.

A code compliant way to use the 10 AWG EGC is to run a feeder to near the outlet with 10AWG EGC. Then run shorter 20 amp branch circuit to the outlet with smaller conductors.
Click to expand...

I disagree. The EGC only has to be increased in size proportionately when the ungrounded conductors are upsized, not to the same size as the ungrounded conductors. See 250.122(B)
 
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