White Paper

May 2007
The PowerPlex Panelboard:
Advancing Panelboard Technology
Understanding component-level protection and its benefits
on installation, maintenance and safety.
The combination of hazardous locations and ignition sources, such as circuit breakers, switches
and motor starters, requires highly engineered protection that prevents a single spark or hot spot from
placing facilities and personnel in danger. These technologies may differ around the globe, but the
goal is the same: keep production running smoothly and safely by preventing electrical devices from
causing ignition of the volatile gases or vapors that may exist within the workplace.
The NEC and CEC standards stipulate that hazardous-
location panelboard enclosures must be designed on the
assumption that vapors or gases have entered the housing and
can be ignited. Appleton products operate safely in hazardous
locations by routing the hot gases from the ignition through
precision-machined “flamepaths.” These pathways allow the
gases to cool to temperatures lower than the ignition point of
the surrounding atmosphere before they are released from the
enclosure.
For decades, North American panelboard enclosures have
had flamepaths incorporated into a flange between the outer
housing’s cover and the body. Large cast-aluminum housings
with numerous bolts to retain the cover on the cast body
were required to maintain the explosionproof integrity of the
enclosure. The Electrical Code typically requires conduit or
cable seals for all incoming and outgoing electrical connections,
as part of the final assembly, to ensure hazardous-location
protection. All this adds significantly to the time, effort and
cost needed to install, maintain and operate panelboards.
The need to reduce downtime and maintenance costs while
preserving safety is driving North American facilities to request
alternative technologies.
IEC Methodology Inspires a Solution
Hazardous location products conforming to International
Electrotechnical Commission (IEC) standards are designed
on the same assumption that a vapor or gas has penetrated the
housing. Where IEC products differ from traditional North
American panelboard design is that the individual breakers
are “factory sealed” rather than depending on the large cast-
aluminum enclosure for protection. These individually sealed
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