codequestion
Banned
- Location
- MD, USA
What is the demand factor when sizing panel feeder for rectifier used in telecommunication tower per nec 2014?
Demand factor rectifier
- Thread starter codequestion
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codequestion
Banned
- Location
- MD, USA
- Occupation
- Licensed Electrician
There is no demand factor or diversity factor for cell tower rectifiers.
Nearly every cell tower I have worked on has come with a pre wired shelter and a 200A panel. We run a 200A service to most of them because that's what's speced.
Nearly every cell tower I have worked on has come with a pre wired shelter and a 200A panel. We run a 200A service to most of them because that's what's speced.
codequestion
Banned
- Location
- MD, USA
How do you determine if ac panel is not overloaded then? Are you saying demand factor for AC feeding ac part of rectifiers is 0? Please help
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jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
Qcroanke (one of our members) builds, installs , and maintains those type of shelters/buildings IIRC.
ron
Senior Member
- Location
- New York, 40.7514,-73.9925
When the batteries go into a deep discharge due to a power outage (if there is a standby gen, it may not start for some reason), the rectifiers, including any redundant ones, go into full recharge of the batteries and carrying the telephone technology load. Unless there is a current limit setup special on that system, there is no demand factor.
One of the cellphone companies I work with call it a dark office load (DOL) condition and often is 2 x the normal load because they also consider redundant HVAC coming on to cool the environment that would have been overheating during that time.
One of the cellphone companies I work with call it a dark office load (DOL) condition and often is 2 x the normal load because they also consider redundant HVAC coming on to cool the environment that would have been overheating during that time.
- Occupation
- Licensed Electrician
I'm saying that the shelter is set up and wired to handle the connected load the same as any building.
Diversity factors are a special area of the code for multi family dwellings and appliances mostly.
- Occupation
- Licensed Electrician
Yep. We've chatted about them on occasion.
200A service with about 60A of total load and that includes the air conditioners. The only 120V loads are the lights and some convenience receptacles that only get used when someone is there so it's a good thing they make us pull full sized neutrals.
codequestion
Banned
- Location
- MD, USA
I have the following panel schedule and when it says total noncoincidental load adjusted service load 0 watts is that correct or should it be more then 0 watts? Also entire panel sechdule total adjusted load is it correct, it does not take into consideration noncoincidental load?
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ptonsparky
Tom
- Occupation
- EC - retired
I believe they are telling you that the loads will not be on at the same time. Either/Or, not both.
codequestion
Banned
- Location
- MD, USA
Yea I understand that but loads that are on are not taken into consideration. See at bottom total load is 41.45kw but when you add 6.2kw + 35.25kw + 17.6kw = 59.05 kw not 41.45kw. Should total adjusted load not be 59.05kw?
I have attached zoom image of load:
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Last edited:
ptonsparky
Tom
- Occupation
- EC - retired
Why are you adding 17.6 kw when it will not be on when the larger loads are?
codequestion
Banned
- Location
- MD, USA
What the note says 4x4400 = 17600 watts are noncoincidental or not on but 5x4400 = 22000 watts are on. So total adjusted load be 22000 + 6200+ 35250 = 63450 watts?
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ptonsparky
Tom
- Occupation
- EC - retired
Use the phase loads in the center columns. Each rectifier is 2200 Watts, not 4400. Look at breaker 2-4 across from the SP on 1-3. After the SP, there is 4400 Watts per stab but still only 2200 per CB.
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