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2.
Fire Sprinkler
System Freeze
Protection
1.
Pipe Freeze
Protection and
Flow Maintenance
3.
Roof and Gutter
De-Icing
4.
Surface Snow
Melting – MI
5.
Surface Snow
Melting and Anti-
Icing – ElectroMelt
6.
Freezer Frost
Heave Prevention
7.
Floor Heating
8.
T
echnical Data
Sheets
Pipe Freeze Protection and Flow Maintenance Design
DETERMInE TRAnSFORMER LOAD
Transformers must be sized to handle the load of the heating cable . Use the following tables
to calculate the total transformer load .
Table 11 Transformer Sizing (Amperes/foot)
Minimum start-up
temperature (°F)
5XL1
8XL1
5XL2
8XL2
12XL2
120
120
208
240
277
208
240
277
208
240
277
–20
0 .119
0 .159
0 .069
0 .067
0 .065
0 .092
0 .087
0 .082
0 .108
0 .106
0 .102
0
0 .105
0 .139
0 .060
0 .059
0 .057
0 .080
0 .076
0 .072
0 .100
0 .098
0 .095
20
0 .090
0 .120
0 .052
0 .051
0 .049
0 .069
0 .066
0 .062
0 .095
0 .093
0 .090
40
0 .075
0 .101
0 .043
0 .042
0 .041
0 .058
0 .055
0 .052
0 .084
0 .083
0 .080
50
–
–
–
–
–
0 .053
0 .050
0 .047
0 .079
0 .077
0 .075
65
–
–
–
–
–
0 .044
0 .042
0 .040
0 .072
0 .070
0 .067
Table 12 Transformer Sizing (Amperes/meter)
Minimum start-up
temperature (°C)
5XL1
8XL1
5XL2
8XL2
12XL2
120
120
208
240
277
208
240
277
208
240
277
–20
0 .391
0 .521
0 .226
0 .221
0 .215
0 .301
0 .286
0 .270
0 .354
0 .347
0 .336
–18
0 .343
0 .457
0 .198
0 .194
0 .188
0 .264
0 .251
0 .238
0 .329
0 .322
0 .312
–7
0 .294
0 .394
0 .170
0 .166
0 .161
0 .227
0 .216
0 .205
0 .311
0 .305
0 .296
4
0 .246
0 .331
0 .142
0 .139
0 .135
0 .191
0 .181
0 .172
0 .276
0 .271
0 .263
10
–
–
–
–
–
0 .172
0 .164
0 .155
0 .259
0 .254
0 .246
18
–
–
–
–
–
0 .145
0 .138
0 .130
0 .233
0 .228
0 .221
Use Table 11 or Table 12 to determine the applied voltage and the maximum A/ft (A/m) at the
minimum start up temperature to calculate the transformer load as follows:
Example: Pipe Freeze Protection – Water Piping
Total heating cable length
315 ft of 5XL1-CR
(from Step 3)
Minimum start-up temperature
–20°F (–29°C) (
from Step 1)
Circuit breaker sizing
30 A
1000
= Transformer
load (kW)
Max A/ft at minimum start-up temperature x Heating cable length (ft)
x Supply voltage
= (0.119 A/ft x 315 ft x 120 V) / 1000
= 4.5 kW
Transformer load (kW)
1000
Max A/ft at –20°F x Total feet
x Supply voltage
