Sealtight power electronics box into which a housing is inserted, said housing incorporating a smoothing capacitor for an electric powertrain, said capacitor being positioned between an internal negative bus and an internal positive bus (BPI, BNI) to said housing, said housing including: - a first positive output terminal that is connected to said positive internal bus and capable of being connected to a first input of one inverter of said powertrain, and a first negative output terminal that is connected to said negative internal bus and capable of being connected to a second input of said inverter; - a second positive output terminal that is connected to said positive internal bus and a second negative output terminal that is connected to said negative internal bus, said housing further comprising: - two attachment lugs (PFP, PFN) for electrical connection, said lugs being insulated from said positive and negative internal buses (BPI, BNI); - one fuse (FUSP), one of the electrical terminals of which is attached to said second positive terminal and the other of the electrical terminals of which is attached to one of said attachment lugs; - and another fuse (FUSN), one of the electrical terminals of which is attached to said second negative terminal and the other of the electrical terminals of which is attached to the other of said attachment lugs, said box including displaced output terminals that correspond to said positive and negative output terminals (BP1, BP2, BP3, BN1, BN2, BN3) of said housing, said housing including a positive output lug that is connected to said positive internal bus and a negative output lug that is connected to said negative internal bus, and said sealtight box including two apertures (OP, ON) that are located facing said positive and negative output lugs, respectively, and a protective cover for said apertures (OP, ON), said cover being provided with a seal, said apertures (OP, ON) being suitable for the insertion of a probe for checking the absence of voltage, and said cover protecting a third aperture made in said box facing an electrical safety device. - a first positive output terminal that is connected to said positive internal bus and capable of being connected to a first input of one inverter of said powertrain, and a first negative output terminal that is connected to said negative internal bus and capable of being connected to a second input of said inverter; - a second positive output terminal that is connected to said positive internal bus and a second negative output terminal that is connected to said negative internal bus, said housing further comprising: - two attachment lugs (PFP, PFN) for electrical connection, said lugs being insulated from said positive and negative internal buses (BPI, BNI); - one fuse (FUSP), one of the electrical terminals of which is attached to said second positive terminal and the other of the electrical terminals of which is attached to one of said attachment lugs; - and another fuse (FUSN), one of the electrical terminals of which is attached to said second negative terminal and the other of the electrical terminals of which is attached to the other of said attachment lugs,