&EPA
United States
Environmental Protection
Agency
Air and Radiation EPA420-R-05-002
January 2005
Truck Stop Electrification
Codes and Electrical
Standards; Notice of Data
Availability [FRL-7783-3]:
Summary of Comments
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EPA420-R-05-002
January 2005
Truck
of Data
of
Transportation and Regional Programs Division
Office of Transportation and Air Quality
U.S. Environmental Protection Agency
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U.S. Environmental Protection Agency
Truck Stop Electrification Codes and Electrical Standards;
Notice of Data Availability [FRL-7783-3]
Summary of Comments
Commentors:
1) Caterpillar, Inc.
2) ConocoPhillips Alaska, Inc.
3) IdleAire Technologies Corporation
4) National Electric Transportation Infrastructure (IWC)
5) Phillips and Temro Industries
6) Shurepower
7) State of Missouri Department of Natural Resources
8) Truck Manufacturers Association (TMA)
9) Washington State Department of Transportation
Potential TSE Code and Electrical Standards
Note: One commentor submitted a draft standard for TSE as part of their comments. (4)
General Comments:
Mexican standards for connections may be an additional area of interest given
the large number of trucks that may pass through our southern borders. (9)
- The location of oilfields in the remote arctic requires operation of diesel trucks
on a 24-hour basis during cold ambient conditions, which is a large part of the
year. In addition, the North Slope oilfields do not have enough power
generation capacity to support the TSE initiative envisioned by EPA and the
U.S. Department of Transportation. We request that EPA clarify in future
rulemaking that the TSE initiative is not meant to apply to industrial
applications such as ours, particularly in arctic conditions on the North Slope
of Alaska. (2)
- We would like to express our support for the effort to develop uniform
national standards for truck stop electrification (TSE) infrastructure. As the
number of manufacturers and users of TSE technology grows, the lack of
uniform standards could lead to stranded investments, damage to TSE
equipment and, worst of all, safety hazards. (7)
On-Board System Power Needs
• What is the kW power needs? Is it <3 kW, 3-6 kW, or >6 kW?
Power availability ranging from 3-6 kW is needed (6), (5)
Based on analysis and study of class 8 trucks equipped with sleeper cabs, and
considering future trends, we recommend 5kW (with some allowance for
power factor due to lagging loads, to arrive at 7.2 kVA). (1)
It depends primarily whether the truck is used extensively in cold weather
environments, in which case, it is likely to be equipped with a block heater, as
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well possibly, with an oil sump and fuel heater. Peak loads without this
equipment can range to over 7kW; with this equipment, the figure can
increase to over lOkW. (8)
- Over 3 million hours of service data has been compiled into a forecasting
model to project TSE power demands under varying weather conditions. This
empirical evidence shows that TSE, taken in terms of a national average,
requires an annual power demand of 1.25 kW per space to maintain comfort
and provide needed power to accessories. Peak power draw by definition is
greater than this nationwide average. Under conditions of extreme cold, the
maximum power draw/peak load could reach or exceed 6kW per space. (3)
• Describe the types of devices and their kW needs when operated?
- HVAC - heater (2.5/5kW), AC compressor (1.5 kW), fans (.2 kW)
Interior Electronics - .2 kW
Block Heaters - 1.5 kW (@120Vac) (3)
A/C compressor - up to 4 kW, electric heat up to 3kW, battery charging 0 -
3kW, blowers & lights 0 - 1 kW. Appliances up to 2 kW. (1)
- HVAC 1.2 - 2.5 kW; Block Heater 1 .OkW -1.5kW; Lights .200kW; Oil Pan
Heater .150kW-.300kW; Microwave 1.0 kW ; Refrigerator .140kW; Fuel
Heater 1.0 kW; Television .150kW ; Fuel/Water Sep 0.06 kW (5), (6)
- Television 0.75 kW; VCR or DVD 0.75 kW; Refrigerator 0.180 kW;
Microwave 1.4 kW; HVAC 4.4 kW; Blockheater 2.5 kW; Fuel heater 0.350
kW; Battery charger 0.60 kW (8)
• Should we use peak power needs?
- No. (1)
- Yes. (6), (8)
- Duty cycle graphs of equipment demand versus most probable maximum
occupancy and/or weather should be incorporated into the power needs to
provide a reasonable value for expected power demand. An example of this
can be seen in Article 220 of the NEC where demand factors are applied to
design loads. Demand factors for TSE should be developed that take
advantage of empirical data and allow for reasonable design constraints. (3)
• Should we follow existing codes for feeder and demand calculations or does
this technology warrant specific codes to follow?
Since current NEC guidelines do not take into consideration the unique
characteristics of TSE, it should be considered part of the TSE implementation
to also develop specific codes within the NEC. (3)
- Yes. (1)
Standard land-side wiring standards and practices are likely to be sufficient.
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Precautions need to be taken, however, to design wiring, receptacles, and
plugs to quickly disconnect and be electrically protected if a driver
inadvertently pulls away without disconnecting the plug. (8)
What are the future trends?
- Future trends should be those that allow for truck accessories (including
HVAC) to be connected to AC shore power. (3)
As land-based connections become more prevalent, the number of
components and power requirements may increase. Drivers will acquire
additional components to match the comfort and convenience of their homes.
(6)
There is a trend to accumulate and use more electrical devices, which is partly
offset by many appliances being designed with higher energy efficiencies. The
new hours of service are expected to have an impact on the trucking industry
and TSE. Trucks will need electrical power for cab temperature control
(heating or air-conditioning), PLUS, electrical power for entertainment. (1)
Future trends are as follows: Dedicated truck stop parking spots will be
increasingly hard to find at locations where drivers want to stop, thus, stand-
alone solutions will be increasingly important; Public displeasure with idling
trucks will increase; Fuel and engine maintenance costs will continue to
increase; therefore truck operator demand for these technologies will increase;
Just-in-time delivery operational demands and hours-of-service rule changes
will make stopping at remote truck stops less appealing. Drivers will want to
stage their stops very close to origin and destination points; Demand for
internet and entertainment connections is increasing, as is demand for full
household capabilities (water & sewer). (8)
Future trends will most likely see hotel and vehicle power loads combined
under a single load. (5)
Will power needs increase or decrease?
It appears that peak power needs will decrease as more efficient methods for
placing equipment on-board are developed. An example of this would be the
decreased thermal loss when delivering HVAC directly from inside the truck.
However, the overall average power needs inside the truck could increase
(from the current 1.25 kW/space) as drivers become aware of more uses for
AC power in the truck cab. (3)
Power demands will likely increase. (5), (8)
Demand will likely increase, but be partially offset by using increased
capabilities in power management systems and by leveraging and using on-
board battery systems during transient peak electrical power demands. (1)
- Even if the components increase in the cab, measures can be taken to decrease
power demand. Although the total and average demands may increase,
existing technologies can drastically reduce the peak loads (6)
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ii. Off-board Power Needs
General Comment: We suggest that the evaluation also account for power constraints
that may be present at public rest area facilities (perhaps standardized 120V or 240V).
(9)
• What voltage and amperage configuration will supply the off-board needs?
Should it be 120V, 240V single phase, 280V single phase or some other
voltage?
Recommendation for use of 120-volt and 208-volt AC power. (3), (4)
- We recommend that initially two 120VAC - 20amp and one 120/208VAC -
30amp outlets be available to drivers. If future trends dictate that all OEM
manufacturers are supplying the 120/208 VAC connection, a shift to
exclusively providing the higher power outlet will be considered. If a 120/208
VAC - 30amp connection is provided, the block heater wiring can be
integrated into a single plug. (6)
Single phase 240-Volt AC at 30 amps, and use of a 4 wire configuration is
recommended. (1), (5)
- It is clear that we need to design our products to enable our customers to
simultaneously use as many 120V AC "household" items as possible. A
significant hurdle, however, is the need, in many cases, to be able to also
power engine block, oil sump, and fuel heaters (in winter) and HVAC (in
summer), all which run on 120V AC. A better solution would be to leave the
engine block, oil pan, and fuel filter heaters on a separate 120VAC
connection. (8)
• What amperage configuration will best provide the power
requirement? Is it 20, 30, 50, or some other amperage?
30 amp service. (3), (8), (5)
- Recommend that initially two 120 V-20 amp and one 12/208 V-30
amp outlets be available to drivers. (6)
• What are the power needs for the transportation refrigerator units?
- "Interior-hauling" vehicles (those that transport goods to the Interior US) that
have the capability to connect to shore power, use 208/3/30 for the required
shore power connection. (3)
- Inquiries to the major TRU manufacturers indicate that most TRUs can be
configured to accept 208VAC 3-phase power.(6)
We defer to our colleagues at the Truck Trailer Manufacturers Association for
the answer to this question. (8)
- Large trailer reefers require a much higher power level than needed for truck
cabs for hotel loads. A 30 kW reefer unit parked in the sun needs 30 kW.(l)
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• Will a voltage above 120V present problems for existing heaters on the
market? Or does this emphasize the need for truck OEM's to install
integrated block heaters into the TSE design?
Any change in the current power requirement of an automotive component
will cause "problems" in the market. The need to move away from 120Vac for
block heaters seems insignificant due to 120Vac always being necessary
inside the truck (for accessories) and for the minimal improvement in
efficiency by moving to higher voltages on block heaters. In either case, the
TSE shore power distribution would be designed to offer either 120Vac or
208Vac. (3)
Voltage above 120 V will present problems for existing heaters on the
market. (8)
We recommend that trucks continue the long-standing practice of plugging in
a separate 120 V cable for the engine block heater to handle extreme cold
conditions. (1)
HI. Connection Compatibility and Safety
General Comment: If RVs and trucks are meant to have compatible
connections, then competition between vehicle types for space may be an
issue. Also, if public rest areas are used for electrification, foolproof systems
of connections (or connection indicators) are needed so that pulling away
without disconnecting would not harm persons or equipment (9)
• What plug configuration should be used?
- There are two pedestal outlet configurations that will meet most truck needs
and will use readily available and proven plug configurations.
o The first configuration is all 120VAC and has two 20 amp GFCI
outlets and one 30 amp ground outlet. The 30 amp outlet is NEMA
TT-30R, which is used by a majority of RVs. One of the two 20
GFCI outlets is used for vehicle (block heater) loads while the other is
used for small HVAC.
o The second configuration will see the inclusion of a NEMA 14-3OR
outlet. The outlet has 4 wires with 2 hot 120VAC connections, a
ground and neutral. (1), (5)
It will be necessary and appropriate to consider using a twist/lock style plug
that will only energize if/when properly installed. Something capable of
delivering 208Vac and up to 30 amps will be needed to support TSE. We
suggest exploring a TSE-specific configuration, with breakaway capabilities.
(3)
- We recommend two outlets with the dual (or "T") configuration that can
accept either 15 or 20 amp 120VAC plugs (NEMA 5-15P or 5-20P). This
outlet should accommodate either plug and be rated at 20 amps. We
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recommend either a 120/240 VAC or 120/20 8 VAC NEMA approved
receptacle rated for SOamps (over 6kW total power). (6)
Currently, a standard 3-prong plug is most widely used. If in the future, a 240
VAC line at 30 amps is provided, a standardized plug should be used. (8)
Should the block heater connection be considered as part of the truck-mounted
TSE system?
• Should power management be required, and if so where should it be installed, on
the truck or within the connection facility?
- Although power management should be a design requirement for the truck
and the facility, it will be imperative that the facility is designed to handle
power distribution to all variations of truck designs in a safe manner. (3)
Power management should be installed within the TSE facility. (8)
- If power management or "load management" is to be recommended or
required, it should be located on the vehicle (6)
A power manager controller will be required to handle(manage) the electrical
power needs. Its location needs to be on-board the truck so that power
management schemes can be tailored to best address the needs, or the devices,
that the customer has installed and is using. (1)
• Should multiple configurations be available on a percentage of use basis, as is
done at RV campsites?
It is reasonable to expect that users would be charged on the basis of how many
lines/circuits they used and only be charged for the power they consume (8)
• How should the user be required to interface with the TSE system for questions
and payment?
The user interface should take place inside the truck. However, it could be said
that this aspect of TSE is not one that should be within the codes and standards
but instead up to the facility. (3)
- NY's TSE sites are demonstrating a payment system that addresses customer
needs. A kiosk or ATM station should be utilized that accepts credit/debit/or fuel
card payment, which activates the pedestal for the select number of hours (1)
• What type of safety considerations should be included in developing the TSE
system?
- Grounding standards, in addition to normal safety considerations, must limit
interference with onboard electrical and electronic systems.(S)
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- Ground fault protection, over-current protection, weather-proof plugs and
receptacles. (1)
• Which grounding standard should be adopted for truck on-board and facility
systems?
- UL/CSA (6), (8)
- The truck frame should be grounded and GFI circuitry implemented (1)
• Should power be distributed in any certain manner?
It should only be required that all codes and safeguards are followed recognizing
the design setting.. .the truck stop environment. (3)
- We believe this is best left to the truck OEMs and suppliers of idle reduction
systems (1)
GFCI and circuit protection should exist at the power source and/or on the
vehicle. General safety standards as recommended by NEC and local codes
should also be followed. (6)
• Should power be available at any distance away from the vehicle?
- There may be an occasional need/desire to operate some 120VAC electrical
devise outside a parked vehicle (8)
Any TSE design should allow for safe user interface via delivery module or cord
so long as the distance from the truck to the TSE interface is within an allowable
distance for proper power distribution. (3)
- Distribution should be limited to avoid excessive voltage drop and cable size. The
national TSE code/standard needs to address pedestal designs (1)
• Should electrical safety measures (GFCI, fuses, breakers, etc.) be present on the
truck, at the connection facility, in the connection wiring, or a combination of
these?
- Combination as needed for safety (8)
Electrical safety must be addressed on all locations of the truck and facility. (3)
The safety measures should be installed at the connection facility (1)
• What sort of safeguards should be in place to verify that the driver only
energizes his/her parking space?
- "No Pay/No Power" requires that the driver not only attempt to pay for service
but is also approved first before power is supplies to any connection to the truck.
This also would require that the system be designed such that
payment/transactions cannot begin unless the user has plugged in properly. (3)
- TSE systems should be "safe" regardless of whether power is energized or not (1)
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• What safety measures (like auto-eject connectors or break-away connections,
engine/transmission/emergency brake system interlocks, visual indicators, or
other equipment) should be integrated into the TSE system to prevent structural
damage, should users pull away while still connected?
All aspects of the design that interface with the driver should incorporate
breakaway features (3)
- Break away cord or plug (5), (6), (8)
Safety measures should be added into the pre-trip installation (8)
Perhaps a lock box or lock-out device (5), (9)
- One of the following safety measures should be required: 120VAC -15&20amp
cords; Auto-eject connectors; Transmission or brake interlock; or Visual (dash
indicator) and audible (buzzer/chime). An auto-switching device (between
onboard and off-board power sources) is recommended when the vehicle is
capable of generating its own power. (6)
- It should be left to the truck OEM, provider of idle-reduction solution system, and
the customer. A number of measures could be used, such as eliminating engine
starting and/or parking break release, to activating warning lights and horns, if the
vehicle engine is started with TSE connected. We also recommend a cable in-line
breakaway connector be used to minimize damage to both the pedestal and the
truck mounted outlet. This in-line cable breakaway connector should be
approximately 2 feet from the truck mounted connector or at a length so as not to
drag on the ground by a moving truck. (1)
• Should tamper-loop monitoring be required?
- Yes. This aspect of the design is far too "easy" and sensible to not be considered a
requirement. The "Monitoring" of this system is paramount and forces TSE
implementers to ensure that they have systems in place to watch and manage the
power distribution safely. (3)
- No. (1)
• Are standards required to ensure safe power supply switching between on-board
and off-board power sources?
It should only be required that services are not offered until proper connection is
established and payment of service is verified (3)
- Yes, there is a potential for 3 separate AC power sources: 1. TSE 2. APU 3. AC
Inverter (1)
Generally accepted design practice dictates that if a method of powering the 120
VAC system is on board the truck, the system will automatically detect power at
the land connection and disconnect the onboard 120 VAC power source (8)
• Should open service neutral protection be standardized on truck mounted
systems?
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- Yes. (1), (3), (8)
iv. System Design
General Comment: The electrical grid standards for truckstops should be shown in the
NEC article 551 much in the same manner as those for RV parks and marine boatyards.
The electrical standards for trucks themselves should be written as a SAE Recommended
Practice. (5)
• What steps should be taken to ensure that modularity of both the truck-mounted
and facility-based TSE is ensured?
Implementation of national codes/standards will help promote and ensure this. (1)
• How should wiring systems of the truck-mounted systems delineate AC and DC
wiring or high and low voltage wiring (color-coding)?
- We are not aware that any standard color coding exists for this purpose.(S)
- Recommend use of bright orange coloring for the high voltage DC wiring, such as
the SAE hybrid vehicle standard. (1), (6)
• What location on the truck (incorporating safety, visibility, and user
preferences) should be designated as the standard location for the installation of
the truck-mounted TSE connection (e.g., driver side, passenger side or front of
vehicle, fender or cab area)?
- Because of the high traffic on the driver-side of the truck (trucker coming and
going) it seems most appropriate to keep any and all connections on the passenger
side. (3)
- TSE connection should be on the driver's side (1), (8), (6)
• How should cab design issues be approached when determining the impact on
cab power requirements?
If cab power requirements can be lowered by making reasonable standards for
truck OEM's, it should be considered most beneficial for both truck and facility to
address those areas inside the cab. One simple example of this would be a
requirement to reduce truck window glass emissivity in the interest of lowering
HVAC loads inside the truck due to radiation. (3)
OEM's should be encouraged to better insulate cabs. This would help with both
sound and thermal efficiency. (1)
- The availability of information about the thermal insulation properties of various
manufacturer's' sleeper berth designs can help drivers/truck buyers decide how
much power they will need to heat/cool these units. (8)
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Should a standardized cab living space be identified to determine the vehicle
electrical load requirements (heating, ventilation, and air conditioning [HVAC]
system capability and cab insulation levels)?
Only for the upfront TSE design parameters should a "standardized cab living
space" be identified. These minimum standards should be set in place to ensure
efficient use of TSE, but the OEM's should enjoy the ability to design trucks to
meet market demand. It is reasonable to assume that over time, as TSE gets
deployed, market forces would drive the adoption of cabs designed to take
maximum advantage of TSE, and would drive OEM's to improve such features
as cab insulation. Here again, for design and recommended practice purposes, it
seems reasonable to average the OEM cab living spaces for items such as
"average volume," "average window area," "average overall insulating
coefficient," "average infiltration rate," etc. to allow for design load requirements
to be estimated. (3)
No, however it may be beneficial to recommend a certain maximum heat
loss/gain rate through the cab envelope to reduce the average HVAC loads. (6)
• What weight allowances should be permitted for truck-mounted TSE
equipment?
Implementing a weight allowance for TSE and idle reducing systems would
provide an incentive to truck owners to add the idling reduction systems with the
knowledge they would not lose truck payload capacity. This would mean that the
current truck class weight limits would need to be raised for trucks with truck
mounted TSE or idle reduction equipment. (1)
- The added weight of this equipment could approach 100 Ibs. (8)
Idle reduction technologies in general often increase the weight of the vehicle.
The 250 pound weight exemption request for idle reduction technologies in the
Energy Policy Act of 2004 should be sufficient for on-board related TSE
hardware (6)
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