The internal arc fault in the metal-enclosed switchgear causes a great threat to the safety of equipment

buildings

and maintenance personnel due to the effect of high pressure. Consequently

internal short-circuit arcing tests in a closed container were carried out under different gap lengths by a series circuit of inductance（L） and capacitance（C）. The arcing characteristics and the change of pressure rise in the closed container were analyzed through the measurement data

such as current

arc voltage

and pressure rise. The results show that the fluctuations of the arc voltage are intensified with the increase of pressure in the closer container. Arc voltage Root-Mean-Square（RMS） has significant randomness with the change of arc current

and increases with the adding of gap length. Arc resistance decreases with the increase of arc current

and the arc resistance per unit gap length is about 6 mΩ/cm. The pressure rise increases with the growth of arc energy

and both show a good relation with linear function. The ratio（kp） of the energy leading to pressure rise on the arc energy is about 45% and the gap length has less influence

and kp decreases with the increase of arc energy and gradually tends to stabilize.