Electrical enclosure

A method of manufacturing an electrical enclosure for protection of cable junctions during a fire emergency, the method comprising the steps of:

• forming a case including an inner cabinet, an outer cabinet, an inner lid, and an outer lid of corrosion-resistant sheet metal by cutting, bending, riveting, and welding;
• forming at least one aperture in the inner cabinet and the outer cabinet;
• sealing seams in the case with an intumescent sealant;
• forming at least one fire-resistive layer by coating fibrous mineral insulation with cement-based fire-resistant material;
• cutting the fire-resistive layer to a size consistent with the inner cabinet and the outer cabinet;
• forming at least one aperture in the fire-resistive layer;
• cutting a fire-resistive block to fit the aperture in the fire-resistive layer and forming at least one aperture in the fire-resistive block;
• assembling the at least one fire-resistive layer to cover an external surface of the inner cabinet and adhering with thixotropic sealant, with the aperture in the fire-resistive layer aligned with the aperture in the inner cabinet;
• sealing edges of the fire-resistive layer with thixotropic sealant;
• placing the outer cabinet onto the fire-resistive layer(s), with the aperture in the outer cabinet aligned with the aperture in the fire-resistive layer;
• welding the outer cabinet to the inner cabinet to form a cabinet;
• welding a corrosion-resistant conduit to the inner cabinet so that the conduit extends a short distance inside the cabinet, and welding a corrosion-resistant conduit to the outer cabinet so that the conduit extends a short distance outside the cabinet, forming a sleeved penetration;
• sealing seams in the case and between the inner cabinet and the conduit and the outer cabinet and the conduit with an intumescent sealant;
• forming at least one lid fire-resistive layer by coating fibrous mineral insulation with cement-based fire-resistant material;
• cutting the lid fire-resistive layer to a size consistent with the inner lid and the outer lid;
• sealing the edges of the fire-resistive layer with thixotropic sealant;
• assembling at least one lid fire-resistive layer to cover the external surface of the inner lid and adhering with thixotropic sealant;
• placing the outer lid onto the lid fire-resistive layer(s);
• welding the outer lid to the inner lid to form a lid, and sealing joints and seams with an intumescent sealant;
• and
• removably securing the lid and the cabinet with fasteners, with fiber gasket and intumescent tape gasket applied where the lid and the cabinet meet to form a fire-resistant enclosure.

A method of protecting cable junctions and the like during a fire emergency, the method comprising the steps of:

• providing a fire-resistant enclosure with a lid, a cabinet, and a sleeved penetration;
• applying intumescent tape to a portion of a fire-resistant cable that will pass through the sleeved penetration;
• passing the fire-resistant cable through the sleeved penetration and forming at least one junction with the fire-resistant cable within the cabinet using junction elements;
• sealing between the sleeved penetration and the fire-resistant cable with intumescent sealing putty;
• securing the lid and the cabinet with fasteners, with fiber gasket and intumescent tape gasket applied where the lid and the cabinet meet to form a fire-resistant enclosure;
• and
• using the sleeved penetration, with the intumescent sealing putty between the fire-resistant cable and the aperture in the fire-resistive block to minimize heat transfer into an interior during a fire emergency.