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SEMI S22-1103a © SEMI 2003, 2005 12 9.1.6 Identification of Facilities Connections 9.1.6.1 Where a neutral conductor is used it should be clearly indicated in th e equipm ent schematic drawin gs and the facilities supply…
SEMI S22-1103a © SEMI 2003, 2005 11
EXCEPTION: Installation considerations for checking safety related aspects of the system that may be impacted
during transportation and storage may be used instead of the packing stipulations of ¶8.12.
8.13 Provisions for Handling Provisions for lifting and handling sub-systems that may cause injury when moved
or lifted during maintenance or service should be provided and documented in the system manuals. See SEMI S8 for
further information.
8.14 Lockout (electrical energy isolation) — Lockable energy isolation devices should be designed into equipment
to provide for safety during service and maintenance tasks. Where it is expected that it will be necessary or
beneficial to work on separately operable parts of the equipment, a separate lockable energy isolation device may be
provided for each such part.
8.15 Suspension of Safeguards General energy isolation, local energy isolation, or safe work procedures should
be used when there is a suspension of safeguards. These procedures should be defined in the maintenance manual.
9 Facilities Electrical Connection
9.1 Incoming Supply Conductors
9.1.1 Equipment should be designed to receive incoming electrical power from the facility to a single feed location
which terminates on the specified main disconnecting means. This main disconnecting means, when opened, should
remove all electrical power in the equipment from the load-side of the main disconnecting means.
EXCEPTION 1: Equipment with more than one electrical feed should be provided with provisions for energy
isolation (“lockout”) for each feed and be marked with the following text, or the equivalent, at each main
disconnecting means: “WARNING: Risk of Electric Shock or Burn. Disconnect all [number of feed locations]
sources of supply prior to servicing.”
EXCEPTION 2: Multiple units mounted separately with no shared hazards and without interconnecting circuits
with hazardous voltages, energy levels, or other potentially hazardous conditions may have: separate sources of
power and separate supply circuit main disconnecting means; or separate EMO circuits, where all the above are
clearly identified.
NOTE 21: If general lockout cannot be performed for a specific maintenance or service task the guidance in Section 8.15 should
be followed.
9.1.2 Field installed supply conductors should be connected directly to the main disconnecting means with no
connection to terminal blocks or other devices.
EXCEPTION: This does not apply where the plug of a cord is the main disconnecting means. However, if the plug
of the cord is not the main disconnecting means then field installed supply conductors should be connected directly
to the main disconnecting means with no connection to terminal blocks or other devices.
9.1.3 Terminals with hazardous potentials present after the main disconnecting means is placed in the “Off”
isolation position should be identified with an appropriate hazard warning label. The label should be placed inside
the electrical enclosure adjacent to the terminals.
9.1.4 The supply overcurrent protection should be rated adequately to protect components connected to the supply
circuit that do not otherwise have adequate overcurrent protection.
9.1.5 The equipment should be provided with main overcurrent protection devices rated with an interrupting
capacity of at least 10,000 rms symmetrical amperes interrupting capacity (AIC) for circuits rated 240VAC or less,
and at least 14,000 rms symmetrical amperes interrupting capacity (AIC) for circuits rated more than 240VAC.
EXCEPTION 1: Cord connected single phase equipment, rated no greater than 2.4 kVA, may have overcurrent
protection devices with an interrupting capacity of at least 5,000 rms symmetrical amperes interrupting capacity.
When this exception is used, the installation manual should inform the user of the lower AIC protection provided by
the equipment.
EXCEPTION 2: An equipment subsystem (e.g. mini-environment ventilation) rated no greater than 2.4 kVA, may
have overcurrent protection devices with interrupting rating of at least 5,000 rms symmetrical amperes interrupting
capacity (AIC).
SEMI S22-1103a © SEMI 2003, 2005 12
9.1.6 Identification of Facilities Connections
9.1.6.1 Where a neutral conductor is used it should be clearly indicated in the equipment schematic drawings and
the facilities supply connection should be labeled “N” or “Neutral”.
EXCEPTION: This marking is not necessary in cord connected equipment where the cord is not installed in the
field.
9.1.6.2 At each incoming supply point, the protective earthing conductor terminal should be identified by the
earthing symbol (see IEC 60417 symbol 5019). In addition to the earthing symbol, other appropriate letter
designations may be applied (e.g. “PE”, “GND”).
9.1.6.3 Installation instructions should be provided for the correct identification and installation of the individual
phases in a three phase system when the improper connection of phases could result in hazardous unintended
rotation or sequence.
9.1.6.4 Each unearthed phase conductor in 3 phase AC power circuits should be clearly indicated in the equipment
schematic drawings, and the facilities incoming supply connection should be identified with one of the following
schemes adjacent to the input terminals:
a) “L1”, “L2”, and “L3",
b) “R”, “S”, and “T”, or
c) “A”, “B”, and “C”.
9.2 Equipment Protective Earthing Connection
9.2.1 A protective earthing conductor should enter the equipment in association with the incoming supply
conductors.
9.2.2 The protective earthing conductor should be copper.
9.2.3 The protective earthing conductor should be sized in accordance with the tables in Appendix 1. See Appendix
1, Tables A1-1 through A1-5 for protective earthing conductor sizes.
9.2.4 The protective earthing conductor terminal should be dedicated for the sole purpose of connecting the
protective earthing conductor to the equipment protective conductors and bonding system.
9.2.5 The protective earthing conductor and its connection to the protective earthing conductor terminal should also
comply with the protective bonding section of this safety guideline (§12).
9.2.6 The protective earthing conductor should not be used as an intentional current carrying conductor for the
power delivery circuit. Currents on the protective earthing conductor from EMC filters are permissible. The
protective earthing conductor may also carry currents that result from incidental inductive and capacitive coupling.
9.2.7 There should be no connection between the supply neutral conductor and the protective earthing conductor or
the protective earthing system inside the electrical equipment.
9.3 Main Disconnecting Means
9.3.1 The main energy isolation capabilities (equipment main disconnecting means) should be in a location that is
readily accessible and should be lockable only in the de-energized position.
9.3.2
For equipment with multiple incoming electrical feeds, all of the main disconnecting means should be
grouped in one area or a marking should be installed at each supply circuit main disconnecting means location
indicating the number of all other supply circuit main disconnecting means.
NOTE 22: Grouping main disconnecting means in one area is preferred.
9.3.3 Supply conductor connections to the main disconnecting means should comply with one of the following:
a) the connections should be located in a separate electrical enclosure installed on or adjacent to the equipment
enclosing the main disconnecting means only. Parts on the supply side of the main disconnecting means in
the equipment which remain energized when the main disconnecting means is switched off should be guarded
(finger-safe) to prevent accidental contact by service personnel; or
SEMI S22-1103a © SEMI 2003, 2005 13
b) the connections should be located within the main electrical enclosure located near the top, with adequate
bending space provided for supply conductor installation and no equipment located above the supply
terminals. Parts on the supply side of the main disconnecting means in the equipment which remain energized
when the main disconnecting means is switched off should be guarded (finger safe) to prevent accidental
contact by service personnel; or
c) the connections should be located within the main electrical enclosure, where other equipment is mounted
above the supply terminals. Parts on the supply side of the main disconnecting means in the equipment which
remain energized when the main disconnecting means is switched off should be guarded to prevent accidental
contact by service personnel or by a tool that may be dropped from above. The opening should be such that a
1-mm (0.04 inch) rod cannot come into contact with the energized parts.
EXCEPTION: Machines with a power consumption totaling 1492 Watts (2 HP) or less may be connected to a
remotely mounted main disconnecting means through a flexible cord, cable, or conduit provided that the main
disconnecting means is in sight from, readily accessible to, and no more than 6 m (20 feet) from the machine
operator work station.
9.3.4 Wire bending space should be provided for the facility supply conductors at the main disconnecting means as
specified by Appendix 1, Tables A1-1 through A1-5.
EXCEPTION: Equipment that meets the wire bending space requirements of NFPA 70 will also meet these criteria.
9.3.5 When placed in the off position the main disconnecting means should satisfy the following criteria:
a) All unearthed conductors of the supply circuit should be disconnected simultaneously.
b) Earthed conductors (neutral or grounded) should not be disconnected.
EXCEPTION: The earthed conductor (neutral) may be disconnected provided that it is disconnected simultaneously
with the unearthed conductors.
NOTE 23: Some jurisdictions require disconnection of the earthed conductor (neutral).
9.3.6 The main disconnecting means should have a minimum of two marked positions, “Off” (isolated) and “On”.
These positions should be clearly marked with IEC 60417 symbol 5008 for “Off” and IEC 60417 symbol 5007 for
“On”.
9.3.7 The actuator of the equipment’s main disconnecting means should be readily accessible and a maximum of 2
meters above the standing surface, measured from the center of the grip.
9.3.8 Each facility main disconnecting means for the incoming electrical supply should be mechanically or
electrically interlocked, or both, with the electrical disconnect enclosure door.
EXCEPTION 1: A main disconnecting means used only for maintenance of lighting circuits within electrical
enclosures should not be interlocked with the electrical enclosure door. A hazard warning label should be provided
when exposed parts may be energized within the main disconnect enclosure when the enclosure door is open.
EXCEPTION 2: Where an attachment plug is used as the main disconnecting means.
EXCEPTION 3: Where a remotely mounted main disconnecting means is provided, a tool is required to open the
equipment enclosure door, and a hazard warning label is attached to the electrical enclosure warning of hazardous
voltage inside and advising isolation of the power before opening.
EXCEPTION 4: The considerations stated in ¶9.3.8 do not apply to equipment rated less than 5KVA that has the
other protections against electric shock stipulated in this document.
9.3.9 The main disconnecting means (lock-out) handle should not disengage from the main disconnecting means
when the enclosure door is opened.
9.3.10 Interlocking should be provided between the main disconnecting means and its associated door to prevent
both of the following:
a) closing of the main disconnecting means while the enclosure door is open, unless the interlock
disconnecting power is overridden by a deliberate action (see §13), and
b) closing of the main disconnecting means until the door hardware is fully closed.