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NEDRA Rulebook

Presented here is the 1998 NEDRA Rulebook. If you have any questions about any of the technical rules please contact our technical representative at tech@nedra.com. A text version of the rules (without the tables) can be found here.  The rules have been unchanged since the original publication, though we are in the process of drafting tighter safety regulations for motorcycles.

A .pdf file is available for downloading for the Class 64 rules which are being formatted for inclusion on this page.

It should be noted that the 1999 NHRA Rulebook (not quoted here) does allow electric vehicles to race. Previous version of the NHRA Rulebook required internal combustion engines. 

All electric vehicle owners are strongly encouraged to purchase a copy of the NHRA Rulebook as it significantly supplements the NEDRA rules below.

NEDRA Rulebook Index
1.0 Introduction
1.1 Overview
2.0 General Regulations
2.1 Engine
2.2 Drive Train
2.3 Brakes and Suspension
2.4 Frame
2.5 Tires and Wheels
2.6 Interior
2.7 Body
2.8 Electrical/Control
2.9 Support Group
2.10 Driver
3.0 Vehicle Classes and Voltage Divisions

1.0 Introduction
The National Electric Drag Racing Association (NEDRA) recognizes that most events will be run on National Hot Rod Association (NHRA) sanctioned tracks, and given the proven safety records of NHRA, we will embrace the general rules (Section 17 of the NHRA 1997 Rulebook), with the following general rules, specific to the needs of Electric Drag Racing. (Note: Text in italics is quoted from the NHRA 1997 Rulebook.)
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1.1 Overview
The following set of rules addresses the differences specific to electric vehicles (excluding hybrid vehicles that will be covered in its own section), versus internal combustion engine vehicles.

  • No Internal Combustion Engine. Electric Vehicles (EVs) have no internal combustion engine.
  • No Fuel, or Flammable liquids, as used for propulsion. EVs do not carry any flammable fluids for propulsion.
  • No Exhaust. EVs require no exhaust system since they do not have an internal combustion engine.
  • Silent. EVs are silent, and therefore, not easy to determine if the vehicle is running or not.
  • High Voltages and Currents are involved. Shock hazards are more of a concern in EVs than in internal combustion vehicles.
  • Large Weight in batteries. Due to the large weight and mass of batteries, this guide addresses the safety issues that may be associated.
  • Caustic liquids, molten metals and plastics may exist under fault conditions, or unusual circumstances.

The "fire hazards"; in an EV are different that those of a fueled vehicle. In a fueled vehicle, the primary hazard is fire (flames). In an EV, the primary hazard is noxious vapors (smoke). The NHRA rules are focused on protecting the driver from flames. In NEDRA, we must focus on protecting the driver from noxious fumes. There are two approved approaches to address these smoke hazards. One approach is to place an effective sealed barrier between the driver and potential sources of noxious fumes or vapors (i.e. propulsion system components). This is the sealed compartment approach, and is essentially identical to the approach taken by NHRA. This approach would need to be used if the driver's compartment is unventilated or poorly ventilated. The other approach is to have a well ventilated driver compartment. This is the fully ventilated compartment approach. Historically, in EV racing, this is the method of choice.
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2.0 General Regulations
NEDRA's general regulations are the same as the NHRA General Regulations (NHRA 1997 Rulebook) with the following exceptions:
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2.1 NHRA 1997 Rulebook Section 17.1 (Engine)
This section does not apply, except for sub-sections 17.1.7 "Liquid Overflow", 17.1.10 "Oil System", and 17.1.15 "Vent Tubes, Breather", apply as written.

2.1.1 Throttle
Regardless of class, each car must have a foot throttle incorporating a positive-acting return spring. A positive stop or override prevention must be used to keep linkage from passing over center, sticking in an open position. In addition to return springs, some means of manually returning the throttle to a closed position by use of the foot must be installed on all altered linkage systems, except hydraulically or cable operated systems. Cable throttle systems are permitted. NHRA accepted hand controls for the physically challenged permitted. Choke cables and brazed or welded fittings on steel cable prohibited. No part of throttle linkage may extend below frame rails. Absent of driver input, throttle must self-return to the "off" position.
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2.2 NHRA 1997 Rulebook Section 17.2 (Drive Train).
This section applies as written, with the following addition: Adequate protection from flying commutator bars in the event of an over-speed motor must be provided in order to protect the driver. As an example, the firewall in an ordinary conversion would be sufficient..
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2.3 NHRA 1997 Rulebook Section 17.3 (Brakes and Suspension).
This section applies as written, with the following exceptions:

2.3.1 Because electric regenerative braking is often standard equipment, automated and/or secondary braking systems are allowed.

2.3.2 Electronics may be used to affect or assist brake operation. This is because EVs do not have compression braking capability.

2.3.3 Upgraded braking systems are encouraged.

2.3.4 Three wheel vehicles are eligible for competition. This is because there are a number of commercially manufactured three wheeled EVs.
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2.4 NHRA 1997 Rulebook Section 17.4 (Frame)
Change this section as follows: Minimum 90 inches unless car has electric motor in original engine location, and is shorter than original. (This change pertains to NHRA 1997 Rulebook section 17.4.12 "Wheelbase") Exceptions will be noted in the class requirements.
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2.5 NHRA 1997 Rulebook Section 17.5 (Tires and Wheels)
This section is accepted without changes.
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2.6 NHRA 1997 Rulebook Section 17.6 (Interior).
Sections 6.2 and 6.3 are accepted as written. Section 6.1 is replaced by the following paragraph:
2.6.1 If the sealed compartment approach is being taken, the NHRA rules of section 6.1 are to be followed with the following addition: No high voltage or high current wiring (excluding instrumentation wiring) may be present in the driver's compartment. If the fully ventilated compartment approach is taken, the following will constitute adequate ventilation: Two openings, on opposite sides of the car, with a minimum of one square foot each of open area. If the drivers window is open more than three inches from the top, then arm restraints or a window net is required.
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2.7 NHRA 1997 Rulebook Section 17.7 (Body)
Aside from section 2.7.5 Firewalls, this section is accepted without changes. 2.7.5 Firewalls
If the "sealed compartment" approach from section 2.6 is taken, this section must be adhered to without changes. If the "fully ventilated compartment" approach is taken then protection from a direct path motor plasma must be provided as must be protection from flying commutator bars.
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2.8 NHRA 1997 Rulebook Section 17.8 (Electrical/Control)
1. High voltage wiring must be isolated /separate from the frame. Traction battery packs over 24 volts must be electrically isolated from the frame and chassis of the vehicle.
2. No electronics can be used to sense the tree.

2.8.1 Batteries
Mounting of batteries:
Since there are always a large number of batteries in an EV, and only one or two batteries in an ICE powered vehicle, the standard NHRA rules for battery mounting are overly simplistic for EV application.

Basically, the batteries in an EV need to stay in place and relatively undamaged during a collision or rollover. Towards this end, the mounting system must be designed to withstand 8 Gs in all directions in the horizontal plane (side-to-side or front-and-back directions) and 4 Gs in the vertical plane (up-and-down direction.) This means that the mounting system must be designed to withstand a force that is 4 times the weight of the batteries in the vertical plane and 8 times the weight of the batteries in the horizontal plane. It is acceptable if the mounting system deforms as a result of impact, but the batteries must be effectively restrained. The batteries must be held in place firmly by the mounting system. No shifting or movement of the batteries should be likely during normal operation of the vehicle. In a collision, it is acceptable that the batteries may shift slightly.

Throughout this section, we will refer to a "battery" as one of the modules that make up the "battery pack" of an EV. The batteries used for EVs vary greatly in size and weight. These rules are written to accommodate the great variety of batteries used in EVs. As the sport matures and speeds increase, the collision G forces will increase and thus require stronger mounting systems. Thus, these rules will change as the ETs decrease.

A strap and bolt system not unlike the standard NHRA mounting system can be used, if desired. It is perhaps the simplest battery mounting system. (It is not the best mounting system, however.) The EV rules are slightly different than the standard NHRA rules. It is assumed that the battery is mounted on a flat surface with just the strap and its bolts holding it in position. In this case, the strap and its must be able to withstand an upward force of 40 times the battery weight. This is because the strap and its bolts must prevent the battery from sliding during a collision. If this type mounting system is selected, each battery must have a separate strap.

Each bolt must take 1/2 the total load. Thus, each bolt must be strong enough not to break under 20 times the battery weight. If we do this calculation for a 44 pound battery, we find that a grade 8, 1/4 inch bolt will meet the criterion as will a grade 5, 7/16 inch bolt or a grade 1, 3/8 inch bolt. Table 1 gives maximum battery weights for many typical bolt sizes and grades.

The strap should be designed to withstand a tensile load of 20 times the battery weight as well. Table 2 gives the minimum dimensions for battery straps for bolt sizes and battery weights.

There are many other acceptable methods of meeting the 8 G / 4 G design requirements. For example, if the battery is restrained from sliding by cleats or rails surrounding its base, the strength requirement for the hold-down system decreases greatly. This is because the hold-down bolts or system need only provide the force to meet the 4 G vertical plane requirement and to keep the battery from rolling (not sliding) out of position in the case of the 8 G horizontal plane requirement. The simple strap-only system had to be strong enough to provide enough down-force to keep the battery from sliding side-to-side (or front-to-back.) Thus, cleats or rails (or boxes) can make the system safer and more lightweight.

Table 3 shows the hold-down bolt minimum size requirements for batteries that are mounted in boxes, in racks, or with cleats at the bases. The "battery lbs" column shows the maximum battery weight each single bolt can restrain with cleats, rails, or boxes in use. Using table 3 we can see that each 87 pound battery must have at least one 1/4 inch grade 5 hold-down bolt. Since there typically isn't a hole down through the center of a battery, you can't just use one bolt to hold down a single battery. A single battery has to have a bolt this size on either side. One bolt provides the strength for an impact in one direction (say "front") while the other bolt provides strength for an impact in the other direction (say "rear") They work together to hold the battery in place for an "left-side" or "right-side" impact. Each bolt on either side of a single battery must be strong enough to secure the entire weight of the battery. For example, an 87 pound battery may not be secured using a grade 5 size #10 bolt on either side. This size battery (in a rack, in a box, or with base cleats) could be properly secured with grade 5, size #10 bolts at all four corners or on all four sides, however. Also, grade 5, size #10 bolts could be used in pairs on either side of the battery.

If the batteries are mounted side-to-side, in groups, as they typically are, the "left-side" bolt for one battery may serve as the "right-side" bolt for the adjacent battery. Again using the 87 lb. battery as an example, it is possible to secure four adjacent batteries using five, grade 5, 1/4 inch; bolts. There would be a bolt between each battery and one at either end of the group. All of the above examples assume that the bolts are placed symmetrically about the center of gravity of each battery. Opposite corners, or in the center of opposite sides, are examples of symmetric bolt placement.

Mounting systems other than the two above examples may be used (and are encouraged.) Properly-designed battery boxes have superior crash resistance and energy-absorbing ability than do typical strap, cleat or rail mounting systems. Because of the great variety of designs possible, prior approval is required for systems other than the strap, cleat, or rack mounting systems. Drawings or photographs of the system must be submitted. Engineering calculations must be submitted showing that the system meets the 8 G / 4 G criteria.

It is important that careful thought be given to battery mounting systems. When you are designing a system, remember that the force of the impact acts at the centroid (center of gravity) of each battery. Do separate calculations for front, rear, left-side, right-side, top, and bottom impacts.

The tables give minimum sizes for bolts and straps. It is wise to use more than the minimum. Stepping up a grade or using a slightly larger size bolt or strap is a wise practice.

If the "sealed compartment" approach has been selected. The battery compartment(s) must be sealed if within the driver's compartment or separate from the sealed driver's compartment. All sealed battery compartments must be vented to the outside of the vehicle. If the preferred "fully ventilated compartment" approach is taken, there must be an effective shield or guard between the driver and the batteries. This shield must be designed to prevent flying molten connections, parts of bursting batteries, or spraying liquid electrolyte from hitting the driver.

Fusing of batteries:
Traction battery packs must be fused. The fuse must have a DC voltage rating equal to or greater than the nominal pack voltage. The current rating of the fuse must be lower than the short circuit current that the pack can produce without damage. It is advised that the current rating of the traction battery pack fuse be as low as is practical. If the traction battery pack is divided into two or more distinctly separate locations within the vehicle, it is strongly suggested that each sub-pack have its own fuse. This suggestion will become a requirement in the near future.

Traction wiring:
Traction wiring shall be protected from physical damage. Traction wiring cables run under the car must be run in an manner similar to brake lines or fuel lines. That is, traction power cables must be protected if they are run beneath frame rails and the like. They should be secured from excessive movement. The wiring must be routed in a manner such that the driver could not inadvertently come into contact with hot cable or conduit surfaces should an over-current condition occur. Traction wiring should be routed outside the driver's compartment were practical. When the hood, trunk and access panels are in place and secured, the traction system components, wiring, and connections should be guarded or insulated such that inadvertent contact with live parts over 24 volts is unlikely.

2.8.2 Delay Boxes
This section is not applicable to electric vehicles.

2.8.3 Ignition
Change ignition system to "traction power system." Since electric vehicles are silent when they are "on" some visible indication of a "live" car must be provided. A removable key, actuator, or connector with a triangular red handle or fob at least 3 inches on a side must be used to "turn on" the car. The red triangle must be clearly visible from outside the car when the key, actuator, or connector is in the "power on" position or location. The key, actuator, or connector must be removed from the vehicle before the driver exits, or as the driver exits. It may not be in or on the vehicle when the driver is not in the vehicle. The goal is to allow any unskilled person to easily distinguish an "energized" electric vehicle from a "de-energized" vehicle. Traction battery pack continuity must be broken when the key, actuator, or connector is removed. Physical contacts, not a semi-conducting device, must be used to break the traction battery pack continuity. Thus, the "enable" circuit of a controller may not serve this purpose. There must be a traction battery pack disconnect device (or control for such device) readily accessible to the driver. A contactor or device that is used to throttle the motor may not serve as the required traction battery pack disconnect. Thus, if a contactor is used as part of the throttle control, it may not serve as the required disconnect. This is because a contactor or device that is used as part of the throttle control interrupts large currents and/or closes under load on a repeated basis. Such service greatly increases the likelihood that the device may fail in a conducting mode. Thus, if such a failure occurs, a separate contactor must be present to disconnect the traction battery pack.

2.8.4 Master Cut-Off
Electric vehicles running 1/4 mile ETs lower than 12.00 are required to have a master cut-off as defined by the NHRA rules. Class rules may also require a shut-off. Unlike the NHRA rules, a positive polarity cut-off is not required. The disconnect may interrupt traction battery pack continuity at any logical point.

2.8.5 Starters
This section is not applicable to electric vehicles.

2.8.6 Tail Lights
This section is accepted without changes.
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2.9 NHRA 1997 Rulebook Section 17.9 (Support Group)
All sections are accepted without change with the following exceptions:

2.9.1 Computers:
Due to the very nature of electric vehicles, it is impossible to effectively inspect, regulate, control the function of the many electronic components involved. Aside from sensing the starting tree lights and signals, or remotely controlling vehicle functions, all electronic devices are allowed in electric vehicle drag racing. All vehicle functions must be controlled on board. No off-board control is allowed. Aside from the driver, nothing on the vehicle may sense or observe the track timing lights (or electronic signals) or the timing tree lights (or electronic signals.) The driver must directly initiate any motion of the vehicle. If the driver releases the throttle control, the motor output must quickly return to zero.

2.9.2 Data Recorders:
All data recording and display devices are allowed for electric vehicles. No vehicle function may be controlled off-board.

2.9.3 Telemetry
Telemetry is allowed in electric vehicle drag racing. No vehicle functions may be controlled remotely. This includes communication functions. The remote system may not transmit in any fashion to the on-board telemetry system. Telemetry allowed under the standard NHRA rules is also allowed in electric vehicle drag racing.

2.9.10 Two-way radio communication.
Delete gathering data or from the last sentence in this section. Telemetry may be one-way only. The on-board telemetry system many be only capable of transmitting. It must not be capable of receiving.

2.9.11 Warm-ups
Change engine is running to "traction system is energized." Delete the Top Fuel and Funny Car section.
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2.10 NHRA 1997 Rulebook Section 17.10 (Driver)
This section is accepted without changes.
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3.0 Vehicle Classes and Voltage Divisions
Race Classes
SPStreet Production
MPModified Production
SCStreet Conversion
MCModified Conversion
MTMotorcycle - Trike
GEGo Cart
HSHigh School Street
HMHigh School Modified
CVConcept Vehicle
CSFClass 64
Voltage Divisions
A241 V and above
B193V - 240V
C169V - 192V
D145V - 168V
E121V - 144V
F97V - 120V
G73V - 96V
H49V - 72V
I25V - 48V
J24V and below

Description of the Classes and Divisions
Modified vehicles are no longer street legal whereas street vehicles are licensed to be driven on the roads. An example of a modified vehicle might be one with non-Department of Transportation approved wheels. Production vehicles typically are mass produced cars that are available via car manufacturers, such as the Toyota RAV-EV or GM's EV-1. Production vehicle have been produced to be electric from the beginning unlike conversion cars. Conversion cars were once gas or diesel (or some form of non-electric powered) that have been converted to be electric. Most of the electric cars currently in existence would be classified as conversion vehicles. Two and three wheeled vehicles fall under the Motorcycle/Trike category. The High School categories are for vehicles built and owned by high schools. The same street and modified rules apply to the high school classes.

To determine your voltage division, simply determine your pack voltage. Currently, we are only recording 1/8 mile times for all vehicle class that are in voltage divisions G - J (under 96V).

If you are uncertain of how to classify your vehicle, or have questions about the race classes and voltage divisions, please contact our tech contact and include a description of your vehicle.

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Last modified: 4/23/99