The following detailed description is directed to intumescent swell devices. According to various embodiments, the swell devices disclosed herein can be used alone or in combination with one another to provide heat and/or fire protection for electrical systems, devices, and/or assemblies. According to exemplary embodiments, intumescent electrical devices, intumescent firewall insert boxes, intumescent flanges, and/or intumescent electrical boxes are disclosed herein for use individually and/or in combination with one another. Additionally, the disclosed intumescent electrical components disclosed herein can be used in combination with intumescent electrical device cover plates, intumescent screws, and intumescent gaskets, if desired. Methods for building electrical assemblies and for retrofitting electrical assemblies to provide fire protection also are provided.