ICEA P Short Circuit Performance of Metallic Shields and Sheaths on Insulated Cables. standard by Insulated Cable Engineers. ICEA P SHORT CIRCUIT PERFORMANCE. OF. METALLIC SHIELDS AND SHEATHS. ON. INSULATED CABLES. Approval by. AMERICAN. TEST METHOD FOR MEASUREMENT OF HOT CREEP OF POLYMERIC INSULATIONS. ICEA S ICEA S standard for power cables.
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From the attached sketch one may calculate the resistance as following: The percent voltage drop is the same between conductors as from conductor to ground and should not be multiplied by 3. Shielding which does not have adequate ground connection due to discontinuity of the shield or to improper termination may be more dangerous than non-shielded non-metallic cable and hazardous to life.
Stress cones should be made at all shield terminations. Where electrostatic discharges are of low enough intensity not to damage cable but are sufficient in magnitude to interfere with radio or television reception. The maximum short-circuit current that can flow in a given shield or sheath for a given time, or 3. If the surface of the cable is separated from ground by a thin layer of air and the air gap is subjected to a voltage stress, which exceeds the dielectric strength of air, a discharge will occur, causing ozone formation.
If not grounded, the hazard of shock may be increased. When used in a duct application, XLPE has a lower coefficient of friction for easier, faster pulling.
-p45-482 More specific information on requirements for shielding by cable type is provided in the following table. The Eng-Tips staff will check this out and take appropriate action.
While these cables are applicable to the great majority of cable installations that are on grounded systems, they may also be used on other systems for which the application of cables is acceptable, provided the above clearing requirements are met in completely de-energizing the faulted section.
The shield should operate at or near ground potential at all times.
Shield Materials Two distinct types of materials are employed in constructing cable shields: An increase in contact resistance may occur after cable installation, during service exposed to moisture and heat.
The reactances shown are for Hertz operation. The same considerations apply ieca exposed installations where personnel who may not be acquainted with the hazards involved handle cables.
XLPE MV Jackets Bring Sustainable Benefits
The system short circuit capacity, the conductor cross-sectional area and the circuit kcea opening time should be such that ;-45-482 maximum allowable short circuit currents are not exceeded.
It accommodates various spacing of the conductors and other unique parameters as indicated within the nomogram itself. This combination will ensure a permanent low resistance, which will maintain contact even if the solder melts. Where regulation is an important consideration several factors should be kept in mind in order to obtain the best operating conditions. The maximum time that a given shortcircuit current can flow in a given shield or sheath, or 2.
Insulated Cable Engineers Assoc., Publication No. PRevised – Google Books
Importance of Shielding Where there is no metallic covering or shield over the insulation, the electric field will be partly in the insulation and partly in whatever lies between the insulation and ground.
Transition from moist to dry earth. If you’re a utility engineer or buyer interested in renewable energy initiatives, you should know about Southwire’s line of MV jackets using crosslinked polyethylene XLPE. This diagram can be used to determine the reactance of any solid or concentric stranded conductor. Single conductors should not be installed in individual magnetic conduit because of the excessive reactance.
It is accomplished by means of strand and insulation shields. Connection to aerial lines. For example, the effective area of a composite shield consisting of a helically applied tape and a wire serving would be the sum of the areas calculated from Formula 2 or 3 and P-45-428 1.
To satisfy my own curiosity, I checked a few text books to see if I could corroborate this. The formula also seems to imply that the shield resistance is independent of the diameter ice the shield, which seems wrong to me. Thank you 7anoter4 for your detailed response.
It is recommended that the shield be grounded at cable terminations and at splices and taps. XLPE jackets promise sustainability benefits including: Nonmetallic shields – ieca of either a conducting tape or a layer of conducting compound. Under these conditions the contact resistance may approach infinity, where Formula 2 could apply.
An insulation shield has a number of functions: I am in the process of calculating sequence impedances for a triplexed MCM,