Draft BSR E1.18
Standard for the Selection, Installation, and Use of Single-Conductor
Portable Power Feeder Cable Systems for Use at Less than 601 Volts Nominal for the Distribution of Electrical Energy in the Entertainment and Live-Event Industries
Ep/2002-7003r10.2
For 2006
ESTA Spring (
USITT) Meeting
© 2006 Accredited Standards Committe E1,
Safety and Compatibility of Entertainment Technical Equipment and Practices, and its secretariat, the Entertainment Services and Technology Association. All Rights Reserved.
Crucial End User Reader Notes & Questions on the proposed changes: - Brian Ship....,.
1.4 Definitions
p.17
Proximity Effect: Increased
conductor impedance caused by a
conductor being in close proximity to another
conductor while both are carrying
current.
p.18 Transient
Connector Assemblies (
tails): A short length (usually between 5 and 10 feet long) of
feeder cable with a
connector on only one end, which is temporarily connected to the supply equipment (commonly called “female
tails set” or to utilization equipment (commonly called “male
tails set”).
(FPN) 1 A female
tails set may have male or female grounded
circuit conductor (
Neutral) connectors(s). It may also have male or female grounding
circuit conductor connector(s).
(FPN) 2 A male
tails set may have male or female grounded
circuit conductor (
neutral)
connector(s). It may also have male or female grounding
circuit conductor connector(s).
p.19 Triped: A method of bundling cables together.
(FPN) Triping invariably requires
derating of the
ampacity of single-conductor
feeder cables.
p.20 Part 2 Component Selection for single-conductor
portable power feeder cable systems
p.21 2.1.2.2 Internal Wiring of Distribution Devices and Distribution part of Utilization Equipment: All Internal wiring shall utilize copper busbars with a
current density of 1000 amperes per square inch or listed
switch board
wire that has a temperature
rating of 90̊C or greater.
(???) What grade of copper has that
current density, what’s it’s cubic area for each amperage
rating?
(???) Type MTW ,
THHN and other types of
wire are not suitable when appropriate in
gauge and
rating? As per below, specification: Type SC cable under 24" in length is suitable for use also.
(Note) Switchboard
wire is type XLP - Switchboard. 600 Volt, 90̊C, stranded tinned copper, suitable separator cross-linked polyethylene
insulation,
UL listed.
Stock color gray; others available. SIS/VW-1
Cole # Size
AWG Cond.
Strand Nom. Wall Nom. O.D. Amps * WT Lbs/M
01-5110 14 41 str .031 .135 42 24
01-5111 12 65 str .031 .157 55 33
01-5112 10 105 str .031 .192 72 47
01-5113 8 133 str .045 .290 97 81
01-5114 6 133 str .060 .330 131 115
01-5115 4 133 str .060 .390 172 172
01-5116 2 133 str .060 .480 232 263
01-5117 1 133 str .080 .570 266 347
01-5118 1/0 133 str .080 .620 309 423
01-5119 2/0 259 str .080 .680 355 520
01-5120 3/0 259 str .080 .730 410 640
01-5121 4/0 259 str .080 .810 481 770
*
Ampacity based on a
conductor temperature of 90̊C and an ambient air temperature of 40̊C.
For 18
AWG & 16
AWG; see UL 3173 above. (Type XLP
hookup)
(Cole
Wire & Cable., Inc. Catalog p.A.6)
p.22 2.1.6.1 Cable Size: Cable Size Shall be Number 2, 2/0, or 4/0
AWG. Number 6
AWG shall be permitted to be used as a
grounding conductor when the overcurrent device associated with the ungrounded (hot) conductors is rated at 200A or less.
(Note) #4
AWG feeder cable is no longer acceptable.
p.22 2.1.6.1 Acceptable Materials and Construction: Conductors shall be made of annealed copper wires in accordance with the elongation, finish, and coating requirements of
ASTM B 3 or ATSM B 33.
Portable feeder cables shall utilize flexible copper conductors with a fine
strand Class K or M, maximum
strand size 30
AWG. (Note) Type SC cable is Class K.
p.23 2.2.4 Outdoor Use: When used outdoors, single-pole separable connectors shall be
NEMA 3R “Rain Tight” or protected from the weather.
(???) What is considered to be suitable protection?
(Note) CamLoc style connectors are not
NEMA 3R and plastic bags covering or around them is not suitable.
p.23 2.2.5.2
Panel Mount Connector Termination to Flexible Conductors: Single Pole
Panel Mount connectors shall be terminated to flexible conductors via direct
crimp, double setscrew, listed compression ring terminals or listed mechanical compression connectors (lugs) affixed to the threaded stud of the
connector.
Panel mount connectors utilizing single setscrew termination methods shall not be used.
(???) This would include single lug compression ring terminals?
p.24 2.2.7 Cable Size: Connectors shall be used with a cable size that they are rated for.
(Note) #4 & #6
feeder cable is not acceptable for use with a CamLoc type
plug.
p.25 Part 3 Selection of Single-conductor
Portable Power Feeder Cable Assemblies
p.25 General: Single-Conductor
portable power feeder cable assemblies shall be protected by an overcurrent protection device at their supply
point and any location in the
portable system where the
wire size is reduced. Overcurrent devices shall not be required at points of
conductor size reduction if the assembly is protected by an upstream overcurrent protection device with an
ampacity equal to or less than the
ampacity of the reduced
conductor.
Cables used in single-conductor
portable power feeder cable assemblies shall meet the requirements of 2.1
Connectors used in single-conductors
portable power feeder cable assemblies shall meet the requirements of 2.2.
p.25
Ampacity:
Ampacity of a cable or a
connector shall be limited to a value which will prevent the cable or
connector from reaching a temperature higher than its temperature
rating or the temperature
rating of the equipment it is attached to.
Current in a single-conductor
portable power feeder cable assembly shall be limited by the use of an overcurrent device at the supply
point to a value not greater than that listed in sections 3.3 or 3.4. Under no circumstances shall the overcurrent device protecting the cable have an
ampacity greater than the
ampacity of the cable unless the tap rules of sections 3.4(A), (B) or ( C) apply.
Conductor sizes and ampacities of single-conductor
portable feeder cable assemblies shall be limited to those described in sections 3.31 through 3.3.5.1.
All single-conductor
portable power feeder cable assemblies shall have a temperature
rating of at least 90̊C. This temperature
rating shall apply to all cables, connectors and terminations that are part of the assembly.
p.26
Ampacity of single-conductor
portable power feeder cable assembly: Single-conductor
portable power feeder cable that meets all of the conditions in (A) through (E) below shall be protected by an overcurrent device not greater than the value listed in table 3.3.1 at the supply
point, and at any
point the
wire size is reduced and shall have an
ampacity as listed in table 3.3.1
(A) The cable shall not be installed in a
raceway,
conduit, nipple, or enclosure for more than 24" of its length.
(B) The cable shall not be
bundled, triped,
harnessed,
triplexed, or in a triangular or square configuration.
( C) The cable shall not be stacked, and must be installed in a single layer.
(D) The cable must be installed with no more than a single
point of its circumference (that is less than 15% of its circumference) in contact with anything besides air or less than one cable diameter from any other adjacent object or cable(s).
(E) The cable must be used in an ambient temperature of 30̊C (86̊F) or less.
Table 3.3.1
Ampacity of Cable
Wire Size
Ampacity Maximum Overcurrent Protection
#2 190 100
2/0 300 200
4/0 405 400
(Note) All cable in a distribution
system must be rated for the specified overcurrent protection, there is no stepping down cable size for it’s protected load by the gear
fed by this cable or use of distribution equipment without it’s own overcurrent protection when stepping down the
conductor size.
(Note) By the above specifications (D) & (C), no more than two conductors at any
point can touch. This is unless as appropriate as per Triped de-rating of cable above where it enters a service entrance, is loomed or
bundled in a
cable pick up
point. See table 3.3.3 below
(Note) 24" A specified maximum length inside a switchboard, panelboard,
switch or other piece of equipment (down
line of the overcurrent protection) unless derated in
ampacity as per table 3.3.2 below at both supply
point and inside the device or cable size stepped up at the device to compensate for downrating.
(Note) Very specific de-rating of
conductor ampacities per table 3.3.1.
p.27 3.3.3
Ampacity of a single-conductor
portable power feeder cable assembly
bundled, triped,
harnessed triplexed, or in a triangular or square configuration or stacked, or less than one cable diameter from any othe adjacent object or cable(s)
Single-conductor poertable
power feeder cable that is:
Not installed for more than a total of 24" in a
raceway,
conduit, nipple, or enclosure and;
used in an ambient temperature of 30̊C (86̊F) or less.
Shall have an overcurrent protection device not greater than the value given in table 3.3.3 at the supply
point and at any
point the
wire size is reduced and a shall have an
ampacity as listed in table 3.3.3.
When single-conductor
portable power feeder cable assemblies are
bundled, triped,
harnessed;
triplexed or in a triangular or square configuration; or stacked; or less than one cable diameter from any other adjacent object or cable(s) all of the conductors that are
bundled, triped,
harnessed;
triplexed or in a triangular or square configuration; or stacked; or less than one cable diameter from any other adjacent object or cable(s) shall be counted in the
ampacity calculation of table 3.3.3.
Table 3.3.3
Ampacity of a single, single-conductor
portable power feeder cable assembly
bundled, triped,
harnessed;
triplexed, or in a triangular or square configuration; or stacked; or less than one cable diameter from any other adjacent object or cable(s).
2
Conductors 3
Conductors 4-6 Conductors 7-9 Conductors 10-20 Conductors 21-30 Conductors
Ampacity Maximum
Overcurrent
Protection
Ampacity Maximum
Overcurrent
Protection
Ampacity Maximum
Overcurrent
Protection
Ampacity Maximum
Overcurrent
Protection
Ampacity Maximum
Overcurrent
Protection
Ampacity Maximum
Overcurrent
Protection
#2 174 100 152 100 122 100 106 100 76 75 68 60
2/0 271 200 237 200 190 175 166 150 118 110 107 100
4/0 361 350 300 253 250 221 200 158 150 150 142 125
(Note) By
NEC standards, the
grounded conductor (
Neutral) is considered a
current carrying
conductor, this makes in the above list five
wire feeder cable looms 4-conductor for appropriate ampacities. Six
wire (double
neutral) dual
loom cable assemblies as a standard in many cases, would comply with the above two and three
conductor ampacities for a higher
rating as long as dual
bundled cable assembly run parallel with each other and given qualified supervision over. Neither loomed cable assembly now comply with the below niceties for feeding applications such as a 96 way
dimmer. (Appropriate specific and allowable ampacities of this specific distribution/
dimmer rack feeder cable below covered in specification of allowances for down
rating the
feeder for maximum load of switchboard mounted maximum overcurrent protected equipment given a 640 Amp per
phase maximum draw of specified dimmers before considering feed
thru, convince, supplemental and hard patch devices or outlets installed both “main breakered” and feed
thru).
(Note) Closed Loop installations (below) in specification could compensate for this
ampacity as long as inspected and supervised by qualified technicians but is not normal policy and has it’s own ball of wax in policies as it were in not being a good solution for keeping
feeder cable loomed in
ease of use. Dual parallel conductors given potential back feed situations is also an option but necessitating qualified technicians using it. This is highly dangerous in back feed and looses any use of the feed
thru of other equipment design intent of normal distribution equipment. It also adds to
safety problems of in dual / parallel conductors feeding gear having potentially very exposed male ends on the female side of the
feeder cable. Dual runs even if very equal in cable length is not recommended. It would seem by way of this specification in normal temporary distribution equipment installations,
feeder cable from
Tails, to
jumper to
feeder, should no longer be loomed and now individually laid out.
(???) By way of specification, even if not
bundled, should more than one
conductor touch in a
cable pick or
layout, it is derated. This includes all
feeder cables that touch naturally by way of gravity even if not loomed in being lifted or laid out and not specifically
grouped by means of bundling to be a
banded together tripple or quad pairing unless spaced apart in prevention from touching also against specification for
derating. eeg. On a
cable pick, cables that should touch must be derated. There must be no more than two cables touching at any
point in the
layout. This is difficult in definition by way of
strain relief required by the
NEC at a service entrance or other equipment unless separated or exception in dual conductors by way also of proximity and number of cable separators. There might be some leanancy or implied necessity for conductors to a
point to touch at specified or necessary and or normal binding of the
conductor points given the rest of the cable is separated. Such a waver for all pinch points is difficult to define say as a two screw
strain relief tensioning device as the norm but otherwise in definition of a
cable pick, what will de-rate the ampacities of the cable given even one
point of contact.
(Note) This
derating of
feeder cable by way of surface contact also includes while not specified all other
current carrying conductors or cables in an assembly.
Socapex cable for instance would also count against the
rating of a
feeder cable when more than one
conductor touching a
feeder cable
line.
(Note) This specification by normal
current carrying
conductor defination also includes the (
Neutral)
current carrying
conductor(s) for all intent of touching and de-rating intent.
(Note) This specification for the most part does not at this time does not
address the need,
derating or necessity at times for oversizing or dual parallel runs of the
grounded conductor (
Neutral) in gaining acceptance in the industry. At some
point this might become an addition to these specifications.
p.28 Other than 30̊C (86̊F) Ambient Temperature: When the ambient temperature is other tnan 30̊C (86̊F) the
ampacity in tables 3.3.1, 3.3.2, and 3.3.3 shall be adjusted by the correction factors in table 3.3.4 (A), and the Maximum Overcurrent Protection listed in the table shall be changed to the values in table 3.3.4(B)
(Note) This ambient temperature is going to become another very specific factor in de-rating for outdoor applications for more than 86̊F temperatures given loadings. This 86̊F
design factor for most gear is problematic in losing say 9% of a
conductor or distribution equipment gear’s
ampacity rating once it becomes say 90̊F instead of 86̊F. Given heating from
stage lighting gear, audience factor heating loads on air conditioning and/or just the temperature of the day, once the show starts, this might become a important table to consider for an expected say 0.82
derating for a 120̊F day or other conditions, or say in the shop 96% of expected
ampacity derating during a 90̊F day. Such a
dynamic temperature
shift might be necessary to rate all Ampacities for a maximum expected temperature rather than average one.
(Note) The norm of a 20%
safety factor in amperage of
system calculated load can soak up some of this
derating necessity due to temperature but this reduces it’s intent of being a
safety factor instead of
design factor. For say a show in the summer where the temperatures about the
stage or
feeder might become over 86̊F as potential, in selection of
AWG and it’s
rating, potentially that
feeder should become a factor.
(Note) Table 3.3.4(B) becomes the governing factor for all general tour or show use
feeder cable in further laminating amperage of
feeder cable but load applied in formatting the formula. This table 3.3.4(B) in pre-designed show and
current draw than would seem to be the most important table for cable
sizing, and should be the primary table used assuming the loomed or picked cable does not also factor in.