||NAVSO P-3641A: More Power For The Dollar
Appendix B. Design Review Checklists
for Power Systems and Power Supplies
- Do engineering drawings contain safety notes and/or critical
- Does unit contain hazardous/toxic materials?
- Is a display test function and power-on light or flag available?
- Is there an overtemperature warning light or signal?
- Have "fail-safe" principles been incorporated in the design?
- Can maintenance or adjustment be performed safely?
- Do units of 45 to 150 pounds have provisions for two-man lifting?
- Is equipment designed so that all external components will be at ground
potential at all times?
- Have bleeder resistors, current-limiting resistors, capacitors, shorting
devices, and similar safety precautions been incorporated where required?
- Do resistive bleeder networks consist of at least two equal resistors in
- Have 3-phase power applications been examined for potential safety hazards
regarding fuses, switches, or other operator controlled devices?
- Is there adequate protection against dangerous voltages?
- Are discharging devices that actuate automatically when equipment is
opened provided for potentials above 30 volts?
- Is wiring routed through plugs and connectors so that removal of a plug or
connector will not expose "hot" leads?
- Are fuseholders provided so that only the cold terminal can be touched?
- Are adjacent plugs or connectors keyed to prevent interchanging
- Are assemblies with potentials exceeding 500 volts completely enclosed?
- Do completely enclosed assemblies with potentials exceeding 500 volts have
interlocks without bypass, automatic discharging devices and grounding rods,
- Do voltage test point dividers have at least two equal resistors in
parallel between the test point and ground?
- Have voltage dividers or other such devices to reduce the voltage at test
points to a relatively low potential level been provided when potentials in
excess of 30 volts peak are required to be measured?
- Are ventilation holes small enough to prevent inadvertent insertion of
test probes or fingers?
- Are high voltage points (>30 Vrms/42Vdc) guarded with barriers that are
stenciled with a warning sign advising of the highest voltage available?
- Have overload protective devices been provided where necessary to prevent
overheating of components and wiring?
- Are electrical terminals clearly marked (e.g. + or -, signal or ground)?
- Have fail-safe devices been provided so that a malfunction in one unit or
subassembly cannot cause malfunction in other units or subassemblies, with
resultant serious damage to the system and possible injury to personnel?
- Are electrical cables routed such that they are not near sources of high
Warning Signs & Labeling
- Are sufficient high-potential guards and warning plates provided?
- Have guards or warning plates been provided for protection against high
temperature, moving or protruding components?
- Do display labels for each termination have the same code symbol as the
wire or line attached to it?
- Are completely enclosed assemblies with potentials exceeding 500 volts
clearly marked "DANGER: HIGH VOLTAGE (maximum voltage) VOLTS" (Reference
ANSI-Z35.1 for color-coding)?
o Are warning signs in accordance with
the design and color-coding requirements (e.g., ANSIZ3 5. 1 latest revision)?
- Is there a warning plate reading "DANGER-do not energize this equipment
unless frame and all exposed metal components are grounded" attached to the
front panel of equipment with leakage current exceeding 5 mA to ground?