An externally gapped line arrester, EGLA, for transmission lines, the EGLA including a series varistor unit, SVU, having a first end and a second end, the SVU configured to be connected between a transmission line and ground, a primary sparkover gap unit serially connected to the first end of the SVU, a secondary gap arranged between the second end of the SVU and ground, and the secondary gap serially connected to the second end of the SVU, a shorting-link device connected in parallel with the secondary gap, and a disconnecting device arranged in the shorting-link device, the disconnecting device configured to open the shorting-link device when the SVU is overloaded. A method for impulse protection performed by an EGLA is also disclosed.