625.41

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charlie b

charlie b

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The city of Seattle is requiring new commercial buildings to include at least a provision for future electric vehicle charging equipment. The requirement is that the service equipment must include the capacity to handle one EV charger for every parking spot in the building. They did provide a table of demand factors, but still the amount of load that this adds to the service rating is huge! For one high rise building we are presently designing, EV charging adds about 1300 amps (@480V) to the service load calculation.

There is a new sentence in the 2014 NEC article 625.41 that allows us to assign an even lower amount of load for EV charging, provided that we design in at least a provision for a future electric vehicle charging "automatic load management system." An Internet search has led me to a number of companies that want to sell me their charging systems. But I have not come across a discussion of a load management system. So my questions are,
  1. Has anyone included a load management system in their design or installation in any recent projects?
  2. Does anyone know of a manufacturer to whom I can turn for information on such a system?
  3. Has anyone taken advantage of the new allowance in 625.41 to reduce the calculated load on a service?
  4. If the answer to #3 is yes, can you share any details?
 
The POCO (Seattle City Light) doesn't need to be ready. Not yet, anyway. The city's requirement is that the design include an allowance for this load. We don't have to install the charging equipment as part of the initial fit out. But we do need to size the main service panel for the future installation, and use, of the chargers.
 
It seems that this will be a huge added expense to developers for a "what if".
 
If Seattle intended to permit the use of load management equipment for this application, I would expect that they would have addressed in in their rules, especially since they gave you demand factors.
 
Extra conduit

Extra conduit

It looks like there are already some EV charging load management systems out there. It's just a system of networked chargers that communicate to limit their total collective load. Here's an example:
http://www.ensto.com/solutions/evcharging/dlm

It seems that just installing a spare conduit to each charger location would do the trick. The conduit is for the future load management data cabling.
 
Is the requirement to just have the capacity on the service for the future charger load only, or the upgraded service and conduits to the charger locations?
 
Not to divert the post, but NYC has a EV charging requirement FYI in the building code

406.2.11 Electric vehicle charging stations.
Parking garages shall be capable of supporting electrical vehicle charging stations in accordance with this section. Electrical raceway to the electrical supply panel serving the garage shall be capable of providing a minimum of 3.1 kW of electrical capacity to at least 20 percent of the parking spaces of the garage.
The electrical room supplying the garage must have the physical space for an electrical supply panel sufficient to provide 3.1kW of electrical capacity to at least 20 percent of the parking spaces of the garage. Such raceway and all components and work appurtenant thereto shall be in accordance with the New York City Electrical Code
.
Exceptions:
1.The provisions of this section shall not apply to parking garages for buildings of Occupancy Group M (Mercantile).
2.The commissioner may waive compliance with this section if the commissioner determines that the parking garage is a temporary facility that will be in service no longer than 3 years.
3.The provisions of this section shall not apply to parking garages for buildings in which not less than fifty percent of the residential units are for households
earning up to sixty percent of the area median income as determined by the United States Department of Housing and Urban Development.
 
don_resqcapt19 said:
If Seattle intended to permit the use of load management equipment for this application, I would expect that they would have addressed in in their rules, especially since they gave you demand factors.
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Seattle's requirement to include provisions for EV charging goes back at least as far as 2008. The load management system first appeared in the 2014 NEC.

 
tkb said:
Is the requirement to just have the capacity on the service for the future charger load only, or the upgraded service and conduits to the charger locations?
Click to expand...
Here is the rule:
All occupancies shall provide adequate capacity to serve a demand load of one electric vehicle charging station per parking space. The demand factor for Level 2 charging stations may be calculated using Table 220.57. Demand factors for Level 3 charging systems shall be calculated at 100% of the nameplate rating. When the size or rating of the Level 2 charging system is unknown, an amperage rating of 40 amps at a nominal voltage of 208 or 240 shall be used for the load calculations.
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The table calls for 100% of the first 3 outlets, 75% of the next 4-20, 50% of the next 21-30, and 25% on the rest. In order to get a significant reduction in the calculated 1300 amps I mentioned in Post 1, I figure I will need a load management system that limits the load to 15-20% of the connected EV charging outlets. What I don't know is whether I can get a load management system that will be able to achieve that level of load reduction, or whether a car can get a sufficient charge if it only is connected to the system 15-20% of the time it sits in the garage.

 
This is what bites my a-- on the energy conservation policies -- require every parking space can be fitted with electric car charging thus increasing the size of the service & all the componants to build it -- what about the CO2 footprint it takes to upsized the copper conductor alone compared to the amount of CO2 footprint saved by running an electric car that has massive batteries needing to be replaced approx every 6 years -- any real numbers on electric cars to fuel burner car ratio? 1 -- 10000?0?0?0?000 lets start with 60 mpg fuel efficiency for suv"s
 
Operating an electric vehicle and recharging it with a coal-fired powerplant emits about half the total CO2 as the same vehicle with a gasoline engine. The biggest reason is an electric traction motor operating at an average efficiency of about 70%, compared to about 7% for an automobile engine.

Upsized conductors are a one-time investment that will remain in service for decades. There's no CO2 footprint associated with operating them.

The geopolitical value of not relying on imported petroleum is almost incalculable.http://english.pvn.vn/
 
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When the size or rating of the Level 2 charging system is unknown, an amperage rating of 40 amps at a nominal voltage of 208 or 240 shall be used for the load calculations.
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So is your 1300 amps figure based on 40 amp EVSEs? Are you allowed to design instead using 20 amp EVSEs?

Cheers, Wayne
 
wwhitney said:
So is your 1300 amps figure based on 40 amp EVSEs? Are you allowed to design instead using 20 amp EVSEs?
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We used 40 amps. The building owner has not chosen to install the EV charging system in the initial build-out. So we don't have a make and model to use as the basis for a service load calculation.

 
charlie b said:
We used 40 amps. The building owner has not chosen to install the EV charging system in the initial build-out. So we don't have a make and model to use as the basis for a service load calculation.
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I'm a little unclear on the design philosophy--if no equipment is being installed now, it's OK to design on the basis of a future "automatic load management system," but not on the basis of future 20 amp EVSEs? There are plenty of 20 amp EVSEs available.

If it would help justify the idea of designing on the basis of 20 amp EVSEs, you could take the equipment savings from a 650 amp reduction in service size, divide it in half, and suggest the building owner use those funds to install a few 20 amp EVSEs at initial build-out. That way you've saved the building owner some money and provided an immediate service to EVs, something more in scale with current EV market penetration.

Cheers, wayne
 
drcampbell said:
Operating an electric vehicle and recharging it with a coal-fired powerplant emits about half the total CO2 as the same vehicle with a gasoline engine. The biggest reason is an electric traction motor operating at an average efficiency of about 70%, compared to about 7% for an automobile engine.

Upsized conductors are a one-time investment that will remain in service for decades. There's no CO2 footprint associated with operating them.

The geopolitical value of not relying on imported petroleum is almost incalculable.http://english.pvn.vn/
Click to expand...

Taking rescoures out of the earth & using them (copper fpr example) you cannot replace is the foot print that needs to be made up for -- the conversation concerns more than one instance -- BTW do we know what the original service size was & what percentage it was increased? Most likely ( in the real world applications) the original calculation could have handled the electric car chargers -- you just said creating electricity from coal fired plants create CO2 so there is always a footprint associated with copper conductors.
 
just provide the empty conduit back to a dummy panel. then if later the building wishes to install charging stations new wire can be pulled and poco can connect power into the other "dummy" panel. this way the sizing is separate. still do the homework though to get wire sizing, this way you can use correct conduit sizes, etc. thus this "what-if" is not a huge extra expense for the main panel.
 
Please allow me to steer this back to the original question. I want to know about load management systems. Has anyone installed such an animal?
 
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