Electricity: conductors and insulators – Boxes and housings
Reexamination Certificate
2000-11-22
2002-10-29
Reichard, Dean A. (Department: 2831)
Electricity: conductors and insulators
Boxes and housings
C174S135000, C174S13800J, C220S003200
Reexamination Certificate
active
06472597
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a spacer for use in a fuse box to space wires from fasteners used to secure a faceplate to the fuse box.
Virtually every house or building that has electricity has a fuse panel contained within a fuse box. The fuse box surrounds the fuse panel and protects it from the environment, as well as preventing persons from inadvertently contacting the fuse panel. The fuse panel may typically include a plurality of circuit breakers that may be toggled as needed to turn on and off electrical circuits. In a typical building, ten, twelve, and fourteen gauge wire (AWG) may be used to connect the fuse panel to the branch circuits, such as outlets, overhead lights and fans, switches, water heaters, furnaces, and air conditioning units. These branch circuit wires carry the electricity from the fuse panel to the branch circuit load. A one hundred Amp fuse panel can have as many as twenty-four circuit breakers, or branch circuits. A two hundred Amp fuse panel may have as many as forty-two circuit breakers. Each 120 V branch circuit, controlled by these circuit breakers, usually requires three wires: the ungrounded conductor (hot), the grounded conductor (neutral), and the grounding conductor (ground). Therefore, a forty-two circuit, two hundred Amp panel could have as many as 126 branch circuit wires.
Electricity is supplied to the fuse panel from an external transformer or power line using much heavier wire. By national code, one hundred Amps require number one aluminum or number three copper (AWG) wire. By the code, two hundred Amps require 4/0 aluminum or 3/0 copper (AWG) wire. Even larger wires are used in larger homes and commercial buildings. As a general rule, the heavier the wire, the more electricity flowing through it.
These heavier wires, because of their larger diameters, are remarkably inflexible. In many installations, the heavy main feeder wires are brought in the bottom and loop around inside of the fuse box to connect to the fuse panel. An electrician installing the fuse box attempts to bend the wires into a desired position against the back of the box. However, many times these wires will bow out of position and contact the internal lip that extends along the front edge of the fuse box.
On most fuse panels, the front cover of the box is screwed on. These screws usually have a sharp tip that extends through a hole in the front cover and a matching hole in the front internal lip of the fuse box. On larger commercial and/or industrial panels, the fuse boxes have clamps that hold the front cover onto the body of the panel. Either the screw or the clamp can (and frequently do) pierce the insulation on the out of position main feeder wires or branch circuit wires. Because the fasteners are metal, it is possible that the fastener shorts the wire to the fuse box, such that a person touching the fuse box may receive a shock, or in extreme situations, be electrocuted. This problem is compounded by the fact that, until the faceplate is removed, visual inspection will not reveal this hazard.
SUMMARY OF THE INVENTION
The present invention comprises placing a spacer within the fuse box to space the internal wires from fasteners that pierce the fuse box. The spacer may be secured to the interior lip of the fuse box and positioned to separate the wires from the terminal ends of the fasteners. A lower surface of the spacer may be shaped to urge the wires away from the faceplate of the fuse box. The spacer may be made of a non-conductive material such as rubber or a polymeric material.
In a first embodiment, the spacer is secured to an inwardly curling lip on the fuse box by an attaching device such as a clip. A fastener, such as a screw, may be inserted through the faceplate, extend through the clip, through the inwardly curling lip, and into the spacer. This effectively precludes the wires from contacting the sharp tip of the fastener. In a variant of this embodiment, not every fastener has a spacer, but sufficient spacers are used to protect the wires from any exposed fasteners.
In a second embodiment, the spacer is secured to the sidewall below the upper lip of the fuse box. Again, a fastener extends through the sidewall to maintain the spacer in the desired position. Wires are inserted under the spacer such that they are precluded from coming into contact with the sharp tips of the fastener.
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Coats & Bennett P.L.L.C.
Estrada Angel R.
Reichard Dean A.
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