Quincy Compressor QOFT 20, Instruction Book

Page: 71 / 84

9.2 Electric cable size
Attention
• An isolating switch and the required fuses must be installed before the
compressor. This is indicated on the connection diagram as "customer's
installation". The required type and maximum size of the fuses are described
below. The fuses protect the supply cables against overload and short circuit.
• The package current, found in the technical data sheet, must be taken into account
when selecting the required type and size of the isolator switch, the fuses and the
feeder cables.
• The isolator and feeder cables of the compressor must be in line with:
a. IEC 60364 ‐ 4 ‐ 523 and IEC 60204 ‐ 1:2006 paragraph 5.3 Supply disconnecting
(isolating) device.
b. The local and national electrical code (USA) or the Canadian electrical code
(Canada).
Local regulations remain applicable if they are stricter than specified above.
• The total voltage drop at the end of the cables must not exceed 10 % of the
nominal voltage. For cable section selection purposes we suggest to add 10 % to
the package current to compensate for any undervoltages that might occur in the
installation.
• Use the original cable entry. See section Dimension drawings.
• To preserve the protection degree of the electric cubicle and to protect its
components from dust from the environment, it is mandatory to use a proper cable
gland when connecting the supply cable to the compressor.
Package current
The Package current mentioned on the technical data sheet is defined as follows:
• Package current is the current the compressor uses:
• At reference conditions
• At 100 % load
• At maximum pressure
• At nominal voltage
• Before service interval (so including fouled filters, etc…)
The pre-described fuses on the technical data sheet are the maximum main fuses to protect the
installed compressor electrical panel.
Maximum fuse size
• The pre-described fuses mentioned in the Technical Data Sheet (TDS) or on the service
diagram are the maximum main fuses to protect the installed compressor electrical panel.
• The pre-described fuse types are to be used.
• Final cable and fuse selection will depend on customer’s installation and local legislation.
• Installing smaller fuses of the same type/class might lead to smaller main feeder cables.
• Always double-check the fuse size versus the calculated cable size. If required, reduce the
fuse size or enlarge the cable size.
• Cable length should not exceed the maximum length according to IEC 60204 (table 10).
• Obey local regulations if they are stricter than the examples mentioned in this document.
Instruction book
9829 3199 74 6 9