An electrical connection sealer includes an outer jacket and a low-viscosity sealant. The outer jacket includes a first piece of heat-shrinkable tubing. The outer jacket has a pre-sealed end and an open end opposite the pre-sealed end. The first piece of heat-shrinkable tubing at the open end is heat-recoverable and forms a cavity for insertion of an electrical connection. The low-viscosity sealant is insertable into the cavity. Upon application of heat to the electrical connection sealer with the electrical connection and the low-viscosity sealant in the cavity of the electrical connection sealer, the low-viscosity sealant flows across and through the first wires and the at least one second wire and the first piece of heat-shrinkable tubing shrinks to encapsulate the electrical connection and seal the electrical connection and the low-viscosity sealant substantially within the outer jacket.