Bussmann Motor Circuit Protection Tables Technical Data
145
©2005 Cooper Bussmann
Columns 1 & 2
Motor horsepower ratings are listed in Column 1. Full load amps from Tables
430.247 through 430.250 are provided in Column 2.
Column 3
Various fuse types are listed in Column 3. The LPJ_SP is a 600Vac, 0 - 600 amp,
time-delay, Class J, “Low-Peak fuse, with a 300,000 amp interrupting rating. The
TCF is a 600Vac, 1 - 100 amp dual-element, time-delay, IP-20 finger-safe fuse with
Class J performance. The LP-CC is a 600Vac, 0 - 30 amp, time-delay, Class CC,
Low-Peak fuse with a 200,000 amp interrupting rating. The LPS-RK_SP and LPNRK_SP are 600 and 250Vac, 0 - 600 amp, time-delay, Class RK1, Low-Peak fuses
with interrupting ratings of 300,000 amps. FRS-R and FRN-R are 600 and 250Vac,
0 - 600 amp, time-delay, Class RK5, Fusetron Dual-Element fuses with interrupting
ratings of 200,000 amps. The KRP-C_SP is a 600Vac, 601 - 6000 amp, time-delay,
Class L, Low-Peak fuse, with a 300,000 amp AC interrupting rating. The DC listed
ratings for these fuses are:
LPJ 1 to 600SP 300Vdc LPN-RK 0 to 60SP 125Vdc
TCF 1 to 100 300Vdc LPN-RK 70 to 600SP 250Vdc
LP-CC
1
⁄2 to 2 8⁄10 300Vdc LPS-RK 0 to 600SP 300Vdc
LP-CC 3 to 15 150Vdc FRN-R 0 to 600 125Vdc
LP-CC 20 to 30 300Vdc FRS-R 0 to 600 300Vdc
Column 4 - Optimal Branch Circuit Protection
There are two distinct levels of protection philosophy provided in this Column. LPSRK_SP, LPN-RK_SP, FRS-R and FRN-R fuses are sized for motor running
“back-up” protection and provide superb short circuit protection at the same time.
LPJ_SP, TCF, and LP-CC fuses are sized a little larger but are even more current
limiting, providing an even greater degree of short circuit protection for the motor
circuit.
All the fuses selected from this column provide short circuit and ground-fault protection for motor branch circuits (430.52), but typically are not the maximum
allowed. Fuses sized in accordance with Column 4 must be used in conjunction
with properly sized motor overload protection such as overload relays or solid state
motor controllers (430.32). This fuse sizing is normally large enough to allow the
overload protective device to operate on overloads without opening the fuse. Yet
for many cases, this fuse amp rating selection is smaller than the maximums
allowed per Columns 5 or 6 (430.52). In some cases, this smaller amp rating
selection may provide the benefits of a smaller size disconnect and better short circuit protection. If a motor has a long starting time, high starting current profile or is
cycled frequently, it may be necessary to use Column 5 or 6.
The LPS-RK_SP, LPN-RK_SP, FRS-R and FRN-R fuses sized per this column provide short circuit and ground-fault protection for motor branch circuits (430.52) as
discussed in the previous paragraph. In addition, these dual-element fuses exhibit
longer time-delay characteristics and can therefore be sized to provide back-up
motor overload protection. The fuse sizing in Column 4 for LPS-RK_SP, LPNRK_SP, FRS-R and FRN-R fuses provides a degree of motor and circuit overload
protection to back-up the normal motor overload protective device. Note: This level
of protection requires a well-designed, true dual-element fuse. The Fusetron
Fuses, FRS-R and FRN-R, and Low-Peak Fuses, LPS-RK_SP and LPN-RK_SP,
are the industry leading dual-element fuses with excellent over-load time-delay
characteristics and current-limiting short circuit ability. The Low-Peak Dual-Element
Fuses have better current-limiting ability than Fusetron Dual-Element Fuses.
The amp ratings in Column 4 are determined by using Column 2 motor ampacity
values and the following:
LPJ_SP & TCF: 150% or the next larger Cooper Bussmann amp rating if 150% does
not correspond to a Cooper Bussmann fuse amp rating.
LP-CC 1⁄2 to 15A: 200% (150% for DC) or the next larger Cooper Bussmann size if
200% (150% for DC) does not correspond to a Cooper Bussmann fuse amp
rating.
LP-CC 20 to 30A: 300% (150% for DC) or the next larger Cooper Bussmann size if
300% (150% for DC) does not correspond to a Cooper Bussmann fuse amp
rating.
LPS-RK_SP and LPN-RK_SP: 130% or the next larger Cooper Bussmann amp rat-
ing if 130% does not correspond to a Cooper Bussmann fuse amp rating.
FRS-R and FRN-R: 125% or the next larger Cooper Bussmann amp rating if 125%
does not correspond to a Cooper Bussmann fuse amp rating.
Column 5 - Branch Circuit Protection, Max. General
Applications
Fuses selected from this column are intended to provide short circuit and groundfault protection for motor branch circuits. Fuses sized in accordance with Column 5
must be used in conjunction with properly sized motor overload protection such as
overload relays or solid state motor controllers (430.32). Column 5 fuse sizing
provides the maximum NEC®Table 430.52 amp ratings for general purpose
applications. It takes into account 430.52(C)(1) Exception No. 1, which allows the
next standard amp rating fuse (per standard fuse amp ratings in 240.6) to be used
if the maximum percentage in Table 430.52 does not correspond to a standard fuse
amp rating. If this Column 5 fuse sizing does not allow the motor to start, then
Column 6 may provide a larger amp rating.
The amp ratings in Column 5 are deter-mined by using Column 2 motor ampacity
values and the following:
LPJ_SP, TCF, LPS-RK_SP, LPN-RK_SP, FRS-R, FRN-R and KRP-C_SP: 175%
(150% for DC motors) or the next larger 240.6 standard fuse amp rating if 175%
(150% for DC motors) does not correspond to a standard fuse amp rating.
LP-CC: 300% (150% for DC motors) or the next larger 240.6 standard fuse amp
rating if 300% (150% for DC motors) does not correspond to a standard fuse amp
rating.
Sizes shown for the LP-CC can also be used for non-time delay fuses such as JKS,
KTN-R, KTS-R, JJN, JJS, and KTK-R.
Column 6 - Branch Circuit Protection, Max. Heavy Start
When the amp rating shown in Column 5 is not sufficient to start a motor, a larger
amp rating is often available by utilizing 430.52(C)(1) Exception No. 2. The amp
ratings in Column 6 are the larger of the amp rating allowed by 430.52(C)(1)
Exception No. 1, or 430.52(C)(1) Exception No. 2. These amp ratings will often be
required when acceleration times are greater than 5 seconds, when plugging or
jogging applications exist, or where there are high inrush currents (such as Design
E or energy efficient Design B motors). (In a few cases, the amp rating in Column 6
may be smaller than the maximum permitted due to the limitation of the fuse type,
such as LP-CC, Class CC fuses that are only available in ratings up to 30 amps. In
these cases, if the amp rating shown is not sufficient to start the motor, select a different family of fuses that meet the requirements.) The amp ratings in Column 6
are determined by using Column 2 motor ampacity values and the following:
LPJ_SP, TCF, LPS-RK_SP, LPN-RK_SP, FRS-R, and FRN-R: 225% or the next
smaller Cooper Bussmann amp rating if 225% does not correspond to a Cooper
Bussmann fuse amp rating.
LP-CC: 400% or the next smaller Cooper Bussmann amp rating if 400% does not cor-
respond to a Cooper Bussmann fuse amp rating.
KRP-C_SP: 300% or the next smaller Cooper Bussmann amp rating, if 300% does
not correspond to a Cooper Bussmann amp rating.
Sizes shown for the LP-CC can also be used for non-time delay fuses such as
JKS, KTN-R, KTS-R, JJN, JJS, AND KTK-R.
Column 7
Horsepower-rated switch sizes given in Column 7 are based on 115% (430.110) of
Column 2. Switch sizes need to be increased when, because of starting requirements, the fuses are sized above the rating of the switch shown in this column.
Column 8
Sizes listed are for general-purpose magnetic controllers (single speed, fullvolt-age for limited plugging and jogging-duty) as shown in NEMA Standards
Publication ICS-2-2000.
Motor Circuit Protection Tables
NEC®Article 430 and Tables Explanation
146
©2005 Cooper Bussmann
Column 9
Copper wire sizes are based upon 125% (430.22) of values shown in Column 2
and ampacities listed in Table 310.16 for 75°C terminals. Although the NEC
®
allows 60°C terminations for equipment rated 100 amp or less, most
equipment terminations have been rated for 75°C conductors. If equipment terminations are rated for 60°C conductors only, the 60°C ampacities must be utilized
and therefore larger conductor sizes may be required than those shown in this column. See 110.14(C) (1)(a)(4).
Column 10
These rigid metallic conduit sizes are based upon copper conductors with THWN
or THHN insulation, Table C8 of Annex C, and 75°C equipment terminals.
Conduit sizes are for three conductors per circuit for three phase motors and two
conductors per circuit for single phase and DC motors. Conduit sizes may need to
be increased if equipment grounding conductors or neutrals are also installed in
the conduit.
If equipment terminations are rated for 60°C conductors only, the 60°C ampacities
must be utilized and therefore larger conductor sizes and conduit sizes may be
required.
Conductors operated in a high ambient temperature may need to be derated.
(See correction factor table at the bottom of Table 310.16.)
Motor Circuit Protection Tables
200Vac Three-Phase Motors & Circuits
12 3 456789 10
Motor Motor Fuse Optimal NEC
®
NEC®Max Minimum Minimum Minimum Minimum
Size FLA Branch Ckt Max for for Heavy Switch NEMA Copper Wire Rigid Metallic
Protection Gen. Applic Start Size Starter THWN or THHN AWG Conduit
Table Table 430.52(C)(1) 430.52(C)(1) 430.110 NEMA ICS 2- or KCMIL Annex C
430.250 430.250 Type Class Exc. No. 1 Exc. No. 2 2000 Table 310.16 Table C8
HP AMPS AMPS
1
AMPS
1
AMPS
1
AMPS Size Size Inches
LPJ_SP J 4 6 6
TCF J
ƒ
66 6
1
⁄2 2.5 LP-CC CC 5 10 10 30 00 14
1
⁄2
LPN-RK_SP RK1 3 1⁄2 66
FRN-R RK5 3 2⁄10 66
LPJ_SP J 5
6
⁄10 10 10
TCF J
ƒ
610 10
3
⁄4 3.7 LP-CC CC 7 1⁄2 15 15 30 00 14
1
⁄2
LPN-RK_SP RK1 5 10 10
FRN-R RK5 5 10 10
LPJ_SP J 8 10 10
TCF J
ƒ
10 10 10
1 4.8 LP-CC CC 10 15 15 30 00 14
1
⁄2
LPN-RK_SP RK1 6 1⁄4 10 10
FRN-R RK5 6 10 10
LPJ_SP J 12 15 15
TCF J
ƒ
15 15 15
1
1
⁄2 6.9 LP-CC CC 15 25 25 30 00 14
1
⁄2
LPN-RK_SP RK1 9 15 15
FRN-R RK5 9 15 15
LPJ_SP J 12 15 17
1
⁄2
TCF J
ƒ
15 15 17 1⁄2
2 7.8 LP-CC CC 25 25 30 30 0 14
1
⁄2
LPN-RK_SP RK1 12 15 17 1⁄2
FRN-R RK5 10 15 17 1⁄2
LPJ_SP J 17 1⁄2 20 20
TCF J
ƒ
17 1⁄2 20 20
3 11 LP-CC CC 25 – – 30 0 14
1
⁄2
LPN-RK_SP RK1 15 20 20
FRN-R RK5 15 20 20
LPJ_SP J 30 35 35
5 17.5 TCF J
ƒ
30 35 35 30* 1 12
1
⁄2
LPN-RK_SP RK1 25 35 35
FRN-R RK5 25 35 35
LPJ_SP J 40 45 50
7
1
⁄2 25.3 TCF J
ƒ
40 45 50 60 1 10**
1
⁄2**
LPN-RK_SP RK1 35 45 50
FRN-R RK5 35 45 50
LPJ_SP J 50 60 70
10 32.2 TCF J
ƒ
50 60 – 60* 2 8** 1⁄2**
LPN-RK_SP RK1 45 60 70
FRN-R RK5 45 60 70
LPJ_SP J 80 90 100
15 48.3 TCF J
ƒ
80 90 100 100 3 6**
3
⁄4**
LPN-RK_SP RK1 70 90 100
FRN-R RK5 70 90 100
LPJ_SP J 100 110 125
20 62.1 TCF J
ƒ
100 – – 100* 3 4** 1
LPN-RK_SP RK1 90 110 125
FRN-R RK5 80 110 125
* Switch size must be increased if the amp rating of the fuse exceeds the amp rating of the switch.
1 Per 430.52(C)(2), if the motor controller manufacturer’s overload relay tables state a maximum branch circuit protective device of a lower rating, that lower rating must be used in lieu of the sizes shown in Columns 4, 5, or 6.
** If equipment terminations are rated for 60°C conductors only, the 60°C conductor ampacities must be utilized and therefore larger conductor sizes or conduit sizes may be required.
ƒ
Class J performance, special finger-safe dimensions.
NEC®Article 430 and Tables Explanation
147
©2005 Cooper Bussmann
Motor Circuit Protection Tables
200Vac Three-Phase Motors & Circuits continued
12 3 456789 10
Motor Motor Fuse Optimal NEC
®
NEC®Max Minimum Minimum Minimum Minimum
Size FLA Branch Ckt Max for for Heavy Switch NEMA Copper Wire Rigid Metallic
Protection Gen. Applic Start Size Starter THWN or THHN AWG Conduit
Table Table 430.52(C)(1) 430.52(C)(1) 430.110 NEMA ICS 2- or KCMIL Annex C
430.250 430.250 Type Class Exc. No. 1 Exc. No. 2 2000 Table 310.16 Table C8
HP AMPS AMPS
1
AMPS
1
AMPS
1
AMPS Size Size Inches
LPJ_SP J 125 150 175
25 78.2 LPN-RK_SP RK1 110 150 175 100* 3 3** 1**
FRN-R RK5 100 150 175
LPJ_SP J 150 175 200
30 92 LPN-RK_SP RK1 125 175 200 200 4 2** 1**
FRN-R RK5 125 175 200
LPJ_SP J 200 225 250
40 120 LPN-RK_SP RK1 175 225 250 200* 4 1/0 1
1
⁄4
FRN-R RK5 150 225 250
LPJ_SP J 225 300 300
50 150 LPN-RK_SP RK1 200 300 300 200* 5 3/0 1
1
⁄2
FRN-R RK5 200 300 300
LPJ_SP J 300 350 350
60 177 LPN-RK_SP RK1 250 350 350 400 5 4/0 2
FRN-R RK5 225 350 350
LPJ_SP J 350 400 450
75 221 LPN-RK_SP RK1 300 400 450 400* 5 300 2
FRN-R RK5 300 400 450
KRP-C_SP L – – 650
LPJ_SP J 450 500 600
100 285 LPN-RK_SP RK1 400 500 600 400* 6 500 3
FRN-R RK5 400 500 600
KRP-C_SP L – – 800
LPJ_SP J 600 – –
125 359 LPN-RK_SP RK1 500 – – 600* 6 4/0 2/PHASE (2)2
FRN-R RK5 450 – –
KRP-C_SP L – 700 1000
LPN-RK_SP RK1 600 – –
150 414 FRN-R RK5 600 – – 600* 6 300 2/PHASE (2)2
KRP-C_SP L – 800 1200
200 552 KRP-C_SP L – 1000 1600 1200 72 500 2/PHASE (2)3
* Switch size must be increased if the amp rating of the fuse exceeds the amp rating of the switch.
1 Per 430.52(C)(2), if the motor controller manufacturer’s overload relay tables state a maximum branch circuit protective device of a lower rating, that lower rating must be used in lieu of the sizes shown in Columns 4, 5, or 6.
** If equipment terminations are rated for 60°C conductors only, the 60°C conductor ampacities must be utilized and therefore larger conductor sizes or conduit sizes may be required.
2 These sizes are typical. They are not shown in NEMA ICS 2-2000.
208Vac Three-Phase Motors & Circuits
12 3 456789 10
Motor Motor Fuse Optimal NEC
®
NEC®Max Minimum Minimum Minimum Minimum
Size FLA Branch Ckt Max for for Heavy Switch NEMA Copper Wire Rigid Metallic
Protection Gen. Applic Start Size Starter THWN or THHN AWG Conduit
Table Table 430.52(C)(1) 430.52(C)(1) 430.110 NEMA ICS 2- or KCMIL Annex C
430.250 430.250 Type Class Exc. No. 1 Exc. No. 2 2000 Table 310.16 Table C8
HP AMPS AMPS
1
AMPS
1
AMPS
1
AMPS Size2 Size Inches
LPJ_SP J 4 6 6
TCF J
ƒ
66 6
1
⁄2 2.4 LP-CC CC 5 10 10 30 00 14
1
⁄2
LPN-RK_SP RK1 3 1⁄2 66
FRN-R RK5 3 6 6
LPJ_SP J 5
6
⁄10 10 10
TCF J
ƒ
610 10
3
⁄4 3.5 LP-CC CC 7 15 15 30 00 14
1
⁄2
LPN-RK_SP RK1 5 10 10
FRN-R RK5 4 1⁄2 10 10
LPJ_SP J 7 10 10
TCF J
ƒ
10 10 10
1 4.6 LP-CC CC 10 15 15 30 00 14
1
⁄2
LPN-RK_SP RK1 6 10 10
FRN-R RK5 6 10 10
LPJ_SP J 10 15 15
TCF J
ƒ
10 15 15
1
1
⁄2 6.6 LP-CC CC 15 20 25 30 00 14
1
⁄2
LPN-RK_SP RK1 9 15 15
FRN-R RK5 9 15 15
*Switch size must be increased if the amp rating of the fuse exceeds the amp rating of the switch.
1 Per 430.52(C)(2), if the motor controller manufacturer’s overload relay tables state a maximum branch circuit protective device of a lower rating, that lower rating must be used in lieu of the sizes shown in Columns 4, 5, or 6.
**If equipment terminations are rated for 60°C conductors only, the 60°C conductor ampacities must be utilized and therefore larger conductor sizes or conduit sizes may be required.
2 These sizes are typical. They are not shown in NEMA ICS 2-2000.
ƒ
Class J performance, special finger-safe dimensions.
148
©2005 Cooper Bussmann
Motor Circuit Protection Tables
208Vac Three-Phase Motors & Circuits continued
12 3 456789 10
Motor Motor Fuse Optimal NEC
®
NEC®Max Minimum Minimum Minimum Minimum
Size FLA Branch Ckt Max for for Heavy Switch NEMA Copper Wire Rigid Metallic
Protection Gen. Applic Start Size Starter THWN or THHN AWG Conduit
Table Table 430.52(C)(1) 430.52(C)(1) 430.110 NEMA ICS 2- or KCMIL Annex C
430.250 430.250 Type Class Exc. No. 1 Exc. No. 2 2000 Table 310.16 Table C8
HP AMPS AMPS
1
AMPS
1
AMPS
1
AMPS Size
2
Size Inches
LPJ_SP J 12 15 15
TCF J
ƒ
15 15 15
2 7.5 LP-CC CC 15 25 30 30 0 14
1
⁄2
LPN-RK_SP RK1 10 15 15
FRN-R RK5 10 15 15
LPJ_SP J 17
1
⁄2 20 20
3 10.6 TCF J
ƒ
17 1⁄2 20 20 30 0 14
1
⁄2
LPN-RK_SP RK1 15 20 20
FRN-R RK5 15 20 20
LPJ_SP J 30 30 35
5 16.7 TCF J
ƒ
30 30 35 30* 1 12
1
⁄2
LPN-RK_SP RK1 25 30 35
FRN-R RK5 25 30 35
LPJ_SP J 40 45 50
7
1
⁄2 24.2 TCF J
ƒ
40 45 50 60 1 10**
1
⁄2
LPN-RK_SP RK1 35 45 50
FRN-R RK5 35 45 50
LPJ_SP J 50 60 60
10 30.8 TCF J
ƒ
50 60 60 60 2 8
1
⁄2**
LPN-RK_SP RK1 45 60 60
FRN-R RK5 40 60 60
LPJ_SP J 70 90 100
15 46.2 TCF J
ƒ
70 90 100 60* 3 6**
3
⁄4**
LPN-RK_SP RK1 70 90 100
FRN-R RK5 60 90 100
LPJ_SP J 90 110 125
20 59.4 TCF J
ƒ
90 – – 100* 3 4** 1
LPN-RK_SP RK1 80 110 125
FRN-R RK5 80 110 125
LPJ_SP J 125 150 150
25 74.8 LPN-RK_SP RK1 100 150 150 100* 3 3** 1**
FRN-R RK5 100 150 150
LPJ_SP J 150 175 175
30 88 LPN-RK_SP RK1 125 175 175 200 4 2** 1**
FRN-R RK5 110 175 175
LPJ_SP J 175 200 250
40 114 LPN-RK_SP RK1 150 200 250 200* 4 1/0 1
1
⁄4
FRN-R RK5 150 200 250
LPJ_SP J 225 300 300
50 143 LPN-RK_SP RK1 200 300 300 200* 5 3/0 1
1
⁄2
FRN-R RK5 200 300 300
LPJ_SP J 300 300 350
60 169 LPN-RK_SP RK1 225 300 350 400 5 4/0 2
FRN-R RK5 225 300 350
LPJ_SP J 350 400 450
75 211 LPN-RK_SP RK1 300 400 450 400* 5 300 2
FRN-R RK5 300 400 450
KRP-C_SP L – – 601
LPJ_SP J 450 500 600
100 273 LPN-RK_SP RK1 400 500 600 400* 6 500 3
FRN-R RK5 350 500 600
KRP-C_SP L – – 800
LPJ_SP J 600 – –
125 343 LPN-RK_SP RK1 450 – – 600* 6 4/0 2/PHASE (2)2
FRN-R RK5 450 – –
KRP-C_SP L – 601 1000
LPJ_SP J 600 – –
150 396 LPN-RK_SP RK1 600 – – 600* 6 250 2/PHASE (2)2
FRN-R RK5 500 – –
KRP-C_SP L – 700 1100
200 528 KRP-C_SP L – 1000 1500 1200* 7 400 2/PHASE (2)2-2 1⁄2
*Switch size must be increased if the amp rating of the fuse exceeds the amp rating of the switch.
1 Per 430.52(C)(2), if the motor controller manufacturer’s overload relay tables state a maximum branch circuit protective device of a lower rating, that lower rating must be used in lieu of the sizes shown in Columns 4, 5, or 6.
**If equipment terminations are rated for 60°C conductors only, the 60°C conductor ampacities must be utilized and therefore larger conductor sizes or conduit sizes may be required.
2 These sizes are typical. They are not shown in NEMA ICS 2-2000.
ƒ
Class J performance, special finger-safe dimensions.
149
©2005 Cooper Bussmann
Motor Circuit Protection Tables
230Vac Three-Phase Motors & Circuits (220-240Vac Systems)
12 3 456789 10
Motor Motor Fuse Optimal NEC
®
NEC®Max Minimum Minimum Minimum Minimum
Size FLA Branch Ckt Max for for Heavy Switch NEMA Copper Wire Rigid Metallic
Protection Gen. Applic Start Size Starter THWN or THHN AWG Conduit
Table Table 430.52(C)(1) 430.52(C)(1) 430.110 NEMA ICS 2- or KCMIL Annex C
430.250 430.250 Type Class Exc. No. 1 Exc. No. 2 2000 Table 310.16 Table C8
HP AMPS AMPS
1
AMPS
1
AMPS
1
AMPS Size
2
Size Inches
LPJ_SP J 3
1
⁄2 66
TCF J
ƒ
66 6
1
⁄2 2.2 LP-CC CC 4 1⁄2 10 10 30 00 14
1
⁄2
LPN-RK_SP RK1 3 6 6
FRN-R RK5 2 8/10 6 6
LPJ_SP J 5 6 7
TCF J
ƒ
66 6
3
⁄4 3.2 LP-CC CC 7 10 12 30 00 14
1
⁄2
LPN-RK_SP RK1 4 1⁄2 67
FRN-R RK5 4 6 7
LPJ_SP J 7 10 10
TCF J
ƒ
10 10 10
1 4.2 LP-CC CC 9 15 15 30 00 14
1
⁄2
LPN-RK_SP RK1 5 6⁄10 10 10
FRN-R RK5 5 8⁄10 10 10
LPJ_SP J 9 15 15
TCF J
ƒ
10 15 15
1
1
⁄2 6 LP-CC CC 12 20 20 30 00 14
1
⁄2
LPN-RK_SP RK1 8 15 15
FRN-R RK5 7 1⁄2 15 15
LPJ_SP J 12 15 15
TCF J
ƒ
15 15 15
2 6.8 LP-CC CC 15 25 25 30 0 14
1
⁄2
LPN-RK_SP RK1 9 15 15
FRN-R RK5 9 15 15
LPJ_SP J 15 20 20
TCF J
ƒ
15 20 20
3 9.6 LP-CC CC 30 30 30 30 0 14
1
⁄2
LPN-RK_SP RK1 15 20 20
FRN-R RK5 12 20 20
LPJ_SP J 25 30 30
5 15.2 TCF J
ƒ
25 30 30 30 1 14
1
⁄2
LPN-RK_SP RK1 20 30 30
FRN-R RK5 20 30 30
LPJ_SP J 35 40 45
7
1
⁄2 22 TCF J
ƒ
34 40 45 30* 1 10
1
⁄2
LPN-RK_SP RK1 30 40 45
FRN-R RK5 30 40 45
LPJ_SP J 45 50 60
10 28 TCF J
ƒ
45 50 60 60 2 10**
1
⁄2
LPN-RK_SP RK1 40 50 60
FRN-R RK5 35 50 60
LPJ_SP J 70 80 90
15 42 TCF J
ƒ
70 80 90 60* 2 6
3
⁄4
LPN-RK_SP RK1 60 80 90
FRN-R RK5 60 80 90
LPJ_SP J 90 100 110
20 54 TCF J
ƒ
90 100 – 100* 3 4 1
LPN-RK_SP RK1 80 100 110
FRN-R RK5 70 100 110
LPJ_SP J 110 125 150
25 68 LPN-RK_SP RK1 90 125 150 100* 3 4** 1
FRN-R RK5 90 125 150
LPJ_SP J 125 150 175
30 80 LPN-RK_SP RK1 110 150 175 100* 3 3** 1**
FRN-R RK5 100 150 175
LPJ_SP J 175 200 225
40 104 LPN-RK_SP RK1 150 200 225 200* 4 1** 1
1
⁄4**
FRN-R RK5 150 200 225
LPJ_SP J 200 250 250
50 130 LPN-RK_SP RK1 175 250 250 200* 4 2/0 1
1
⁄2
FRN-R RK5 175 250 250
LPJ_SP J 250 300 300
60 154 LPN-RK_SP RK1 225 300 300 200* 5 3/0 1
1
⁄2
FRN-R RK5 200 300 300
*Switch size must be increased if the amp rating of the fuse exceeds the amp rating of the switch.
1 Per 430.52(C)(2), if the motor controller manufacturer’s overload relay tables state a maximum branch circuit protective device of a lower rating, that lower rating must be used in lieu of the sizes shown in Columns 4, 5, or 6.
**If equipment terminations are rated for 60°C conductors only, the 60°C conductor ampacities must be utilized and therefore larger conductor sizes or conduit sizes may be required.
2 These sizes are typical. They are not shown in NEMA ICS 2-2000.
ƒ
Class J performance, special finger-safe dimensions.
4 Limited by 600 amp being the largest amp rating for FRN-R and LPN-RK_SP.
150
©2005 Cooper Bussmann
Motor Circuit Protection Tables
230Vac Three-Phase Motors & Circuits (220-240Vac Systems) continued
460Vac Three-Phase Motors & Circuits (440-480Vac Systems)
12 3 456789 10
Motor Motor Fuse Optimal NEC
®
NEC®Max Minimum Minimum Minimum Minimum
Size FLA Branch Ckt Max for for Heavy Switch NEMA Copper Wire Rigid Metallic
Protection Gen. Applic Start Size Starter THWN or THHN AWG Conduit
Table Table 430.52(C)(1) 430.52(C)(1) 430.110 NEMA ICS 2- or KCMIL Annex C
430.250 430.250 Type Class Exc. No. 1 Exc. No. 2 2000 Table 310.16 Table C8
HP AMPS AMPS
1
AMPS
1
AMPS
1
AMPS Size
2
Size Inches
LPJ_SP J 1
8
⁄10 33
TCF J
ƒ
33 3
1
⁄2 1.1 LP-CC CC 2 1⁄4 6 6 30 00 14
1
⁄2
LPS-RK_SP RK1 1 11⁄2 33
FRS-R RK5 1 4⁄10 33
LPJ_SP J 2
1
⁄2 33
1
⁄2
TCF J
ƒ
33 3
3
⁄4 1.6 LP-CC CC 3 2⁄10 66
1
⁄4 30 00 14
1
⁄2
LPS-RK_SP RK1 2 1⁄4 33
1
⁄2
FRS-R RK5 2 3 3 1⁄2
LPJ_SP J 3 2⁄10 66
TCF J
ƒ
66 6
1 2.1 LP-CC CC 4
1
⁄2 10 10 30 00 14
1
⁄2
LPS-RK_SP RK1 2 8⁄10 66
FRS-R RK5 2 8⁄10 66
LPJ_SP J 4
1
⁄2 66
TCF J
ƒ
66 6
1
1
⁄2 3 LP-CC CC 6 10 12 30 00 14
1
⁄2
LPS-RK_SP RK1 4 6 6 1⁄4
FRS-R RK5 4 6 6 1⁄4
LPJ_SP J 5 6⁄10 67
TCF J
ƒ
66 6
2 3.4 LP-CC CC 7 1 5 15 30 00 14
1
⁄2
LPS-RK_SP RK1 4 1⁄2 67
FRS-R RK5 4 1⁄2 67
1
⁄2
LPJ_SP J 8 10 10
TCF J
ƒ
10 10 10
3 4.8 LP-CC CC 10 15 15 30 0 14
1
⁄2
LPS-RK_SP RK1 6 1⁄4 10 10
FRS-R RK5 6 10 10
LPJ_SP J 12 15 15
TCF J
ƒ
15 15 15
5 7.6 LP-CC CC 25 25 30 30 0 14
1
⁄2
LPS-RK_SP RK1 10 15 15
FRS-R RK5 10 15 15
* Switch size must be increased if the amp rating of the fuse exceeds the amp rating of the switch.
1 Per 430.52(C)(2), if the motor controller manufacturer’s overload relay tables state a maximum branch circuit protective device of a lower rating, that lower rating must be used in lieu of the sizes shown in Columns 4, 5, or 6.
** If equipment terminations are rated for 60°C conductors only, the 60°C conductor ampacities must be utilized and therefore larger conductor sizes or conduit sizes may be required.
ƒ
Class J performance, special finger-safe dimensions.
12 3 456789 10
Motor Motor Fuse Optimal NEC
®
NEC®Max Minimum Minimum Minimum Minimum
Size FLA Branch Ckt Max for for Heavy Switch NEMA Copper Wire Rigid Metallic
Protection Gen. Applic Start Size Starter THWN or THHN AWG Conduit
Table Table 430.52(C)(1) 430.52(C)(1) 430.110 NEMA ICS 2- or KCMIL Annex C
430.250 430.250 Type Class Exc. No. 1 Exc. No. 2 2000 Table 310.16 Table C8
HP AMPS AMPS
1
AMPS
1
AMPS
1
AMPS Size
2
Size Inches
LPJ_SP J 300 350 400
75 192 LPN-RK_SP RK1 250 350 400 400 5 250 2
FRN-R RK5 250 350 400
LPJ_SP J 400 450 500
100 248 LPN-RK_SP RK1 350 450 500 400* 5 350 2
1
⁄2
FRN-R RK5 350 450 500
KRP-C_SP L – – 700
LPJ_SP J 500 600 –
125 312 LPN-RK_SP RK1 450 600 – 400* 6 3/0 2/PHASE (2) 1
1
⁄2
FRN-R RK5 400 600 –
KRP-C_SP L – — 900
LPJ_SP J 600 – –
150 360 LPN-RK_SP RK1 500 6004 – 600* 6 4/0 2/PHASE (2) 2
FRN-R RK5 450 6004 –
KRP-C_SP L – 700 1000
200 480 FRN-R RK5 600 – – 600* 6 350 2/PHASE (2) 2-2
1
⁄2
KRP-C_SP L – 1000 1400
*Switch size must be increased if the amp rating of the fuse exceeds the amp rating of the switch.
1 Per 430.52(C)(2), if the motor controller manufacturer’s overload relay tables state a maximum branch circuit protective device of a lower rating, that lower rating must be used in lieu of the sizes shown in Columns 4, 5, or 6.
**If equipment terminations are rated for 60°C conductors only, the 60°C conductor ampacities must be utilized and therefore larger conductor sizes or conduit sizes may be required.
2 These sizes are typical. They are not shown in NEMA ICS 2-2000.
4 Limited by 600 amp being the largest amp rating for FRN-R and LPN-RK_SP.
151
©2005 Cooper Bussmann
Motor Circuit Protection Tables
460Vac Three-Phase Motors & Circuits (440-480Vac Systems) continued
12 3 456789 10
Motor Motor Fuse Optimal NEC
®
NEC®Max Minimum Minimum Minimum Minimum
Size FLA Branch Ckt Max for for Heavy Switch NEMA Copper Wire Rigid Metallic
Protection Gen. Applic Start Size Starter THWN or THHN AWG Conduit
Table Table 430.52(C)(1) 430.52(C)(1) 430.110 NEMA ICS 2- or KCMIL Annex C
430.250 430.250 Type Class Exc. No. 1 Exc. No. 2 2000 Table 310.16 Table C8
HP AMPS AMPS
1
AMPS
1
AMPS
1
AMPS Size
2
Size Inches
LPJ_SP J 17
1
⁄2 20 20
7
1
⁄2 11 TCF J
ƒ
17 1⁄2 20 20 30 1 14
1
⁄2
LPS-RK_SP RK1 15 20 20
FRS-R RK5 15 20 20
LPJ_SP J 25 25 30
10 14 TCF J
ƒ
25 25 30 30 1 14
1
⁄2
LPS-RK_SP RK1 20 25 30
FRS-R RK5 17 1⁄2 25 30
LPJ_SP J 35 40 45
15 21 TCF J
ƒ
35 40 45 30* 2 10
1
⁄2
LPS-RK_SP RK1 30 40 45
FRS-R RK5 30 40 45
LPJ_SP J 45 50 60
20 27 TCF J
ƒ
45 50 60 60 2 10**
1
⁄2
LPS-RK_SP RK1 40 50 60
FRS-R RK5 35 50 60
LPJ_SP J 60 60 70
25 34 TCF J
ƒ
60 60 70 60* 2 8**
1
⁄2**
LPS-RK_SP RK1 45 60 70
FRS-R RK5 45 60 70
LPJ_SP J 60 70 90
30 40 TCF J
ƒ
60 70 90 60* 3 8**
1
⁄2**
LPS-RK_SP RK1 60 70 90
FRS-R RK5 50 70 90
LPJ_SP J 80 100 110
40 52 TCF J
ƒ
80 100 – 100* 3 6**
3
⁄4**
LPS-RK_SP RK1 70 100 110
FRS-R RK5 70 100 110
LPJ_SP J 100 125 125
50 65 TCF J
ƒ
100 – – 100* 3 4** 1
LPS-RK_SP RK1 90 125 125
FRS-R RK5 90 125 125
LPJ_SP J 125 150 150
60 77 LPS-RK_SP RK1 110 150 150 100* 4 3** 1**
FRS-R RK5 100 150 150
LPJ_SP J 150 175 200
75 96 LPS-RK_SP RK1 125 175 200 200 4 1** 1
1
⁄4**
FRS-R RK5 125 175 200
LPJ_SP J 200 225 250
100 124 LPS-RK_SP RK1 175 225 250 200* 4 2/0 1
1
⁄2
FRS-R RK5 175 225 250
LPJ_SP J 250 300 350
125 156 LPS-RK_SP RK1 225 300 350 200* 5 3/0 1
1
⁄2
FRS-R RK5 200 300 350
LPJ_SP J 300 350 400
150 180 LPS-RK_SP RK1 250 350 400 400 5 4/0 2
FRS-R RK5 225 350 400
LPJ_SP J 400 450 500
200 240 LPS-RK_SP RK1 350 450 500 400* 5 350 2
1
⁄2
FRS-R RK5 300 450 500
KRP-C_SP L – – 700
LPJ_SP J 500 600 –
250 302 LPS-RK_SP RK1 400 600 – 400* 6 3/0 2/PHASE (2) 1
1
⁄2
FRS-R RK5 400 600 –
KRP-C_SP L – – 900
LPJ_SP J 600 – –
300 361 LPS-RK_SP RK1 500 6004 – 600* 6 4/0 2/PHASE (2) 2
FRS-R RK5 500 6004 –
KRP-C_SP L – 700 1000
LPS-RK_SP RK1 600 – –
350 414 FRS-R RK5 600 – – 600* 6 300 2/PHASE (2) 2
KRP-C_SP L – 800 1200
400 477 KRP-C_SP L – 1000 1400 600* 6 350 2/PHASE (2 )2
1
⁄2
FRS-R RK5 600 – –
450 515 KRP-C_SP L – 1000 1500 1200* 7 400 2/PHASE (2) 2 1⁄2
500 590 KRP-C_SP L – 1200 1600 1200* 7 500 2/PHASE (2) 3
* Switch size must be increased if the amp rating of the fuse exceeds the amp rating of the switch.
1 Per 430.52(C)(2), if the motor controller manufacturer’s overload relay tables state a maximum branch circuit protective device of a lower rating, that lower rating must be used in lieu of the sizes shown in Columns 4, 5, or 6.
** If equipment terminations are rated for 60°C conductors only, the 60°C conductor ampacities must be utilized and therefore larger conductor sizes or conduit sizes may be required.
4 Limited by 600 amp being the largest amp rating for FRS-R and LPS-RK_SP.
ƒ
Class J performance, special finger-safe dimensions.
152
©2005 Cooper Bussmann
Motor Circuit Protection Tables
575Vac Three-Phase Motors & Circuits (550-600Vac Systems)
12 3 456789 10
Motor Motor Fuse Optimal NEC
®
NEC®Max Minimum Minimum Minimum Minimum
Size FLA Branch Ckt Max for for Heavy Switch NEMA Copper Wire Rigid Metallic
Protection Gen. Applic Start Size Starter THWN or THHN AWG Conduit
Table Table 430.52(C)(1) 430.52(C)(1) 430.110 NEMA ICS 2- or KCMIL Annex C
430.250 430.250 Type Class Exc. No. 1 Exc. No. 2 2000 Table 310.16 Table C8
HP AMPS AMPS
1
AMPS
1
AMPS
1
AMPS Size
2
Size Inches
LPJ_SP J 1
4
⁄10 33
TCF J
ƒ
33 3
1
⁄2 0.9 LP-CC CC 1 8⁄10 33
1
⁄2 30 0 14
1
⁄2
LPS-RK_SP RK1 1 1⁄4 33
FRS-R RK5 1 1⁄8 33
LPJ_SP J 2 3 3
TCF J
ƒ
33 3
3
⁄4 1.3 LP-CC CC 2 8⁄10 6 6 30 0 14
1
⁄2
LPS-RK_SP RK1 1 8⁄10 33
FRS-R RK5 1 8⁄10 33
LPJ_SP J 2
8
⁄10 33
1
⁄2
TCF J
ƒ
33 3
1 1.7 LP-CC CC 3
1
⁄2 66
1
⁄4 30 0 14
1
⁄2
LPS-RK_SP RK1 2 1⁄4 33
1
⁄2
FRS-R RK5 2 1⁄4 33
1
⁄2
LPJ_SP J 4 6 6
TCF J
ƒ
66 6
1
1
⁄2 2.4 LP-CC CC 5 10 10 30 0 14
1
⁄2
LPS-RK_SP RK1 3 2⁄10 66
FRS-R RK5 3 6 6
LPJ_SP J 4
1
⁄2 66
TCF J
ƒ
66 6
2 2.7 LP-CC CC 5
6
⁄10 10 10 30 0 14
1
⁄2
LPS-RK_SP RK1 4 6 6
FRS-R RK5 3 1⁄2 66
LPJ_SP J 6 10 10
TCF J
ƒ
610 10
3 3.9 LP-CC CC 5 15 15 30 0 14
1
⁄2
LPS-RK_SP RK1 5 6⁄10 10 10
FRS-R RK5 5 10 10
LPJ_SP J 10 15 15
TCF J
ƒ
10 15 15
5 6.1 LP-CC CC 15 20 20 30 0 14
1
⁄2
LPS-RK_SP RK1 8 15 15
FRS-R RK5 8 15 15
LPJ_SP J 15 20 20
TCF J
ƒ
15 20 20
7
1
⁄2 9 LP-CC CC 30 30 30 30 1 14
1
⁄2
LPS-RK_SP RK1 12 20 20
FRS-R RK5 12 20 20
LPJ_SP J 17
1
⁄2 20 20
10 11 TCF J
ƒ
17 1⁄2 20 20 30 1 14
1
⁄2
LPS-RK_SP RK1 15 20 20
FRS-R RK5 15 20 20
LPJ_SP J 30 30 35
15 17 TCF J
ƒ
30 30 35 30* 2 12
1
⁄2
LPS-RK_SP RK1 25 30 35
FRS-R RK5 25 30 35
LPJ_SP J 35 40 45
20 22 TCF J
ƒ
35 40 45 30* 2 10
1
⁄2
LPS-RK_SP RK1 30 40 45
FRS-R RK5 30 40 45
LPJ_SP J 45 50 60
25 27 TCF J
ƒ
45 50 60 60 2 10**
1
⁄2**
LPS-RK_SP RK1 40 50 60
FRS-R RK5 35 50 60
LPJ_SP J 50 60 70
30 32 TCF J
ƒ
50 60 70 60* 3 8
1
⁄2
LPS-RK_SP RK1 45 60 70
FRS-R RK5 40 60 70
LPJ_SP J 70 80 90
40 41 TCF J
ƒ
70 80 90 60* 3 6
3
⁄4
LPS-RK_SP RK1 60 80 90
FRS-R RK5 60 80 90
LPJ_SP J 80 100 110
50 52 TCF J
ƒ
80 100 – 100* 3 6**
3
⁄4**
LPS-RK_SP RK1 70 100 110
FRS-R RK5 70 100 110
*Switch size must be increased if the amp rating of the fuse exceeds the amp rating of the switch.
1 Per 430.52(C)(2), if the motor controller manufacturer’s overload relay tables state a maximum branch circuit protective device of a lower rating, that lower rating must be used in lieu of the sizes shown in Columns 4, 5, or 6.
**If equipment terminations are rated for 60°C conductors only, the 60°C conductor ampacities must be utilized and therefore larger conductor sizes or conduit sizes may be required.
2 These sizes are typical. They are not shown in NEMA ICS 2-2000.
ƒ
Class J performance, special finger-safe dimensions.