ICEA P-45-482 PDF
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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For three-phase circuits, use voltage to neutral and resistance and reactance of each conductor to neutral. The ground may be a metallic conduit, a damp non-metallic conduit or a metallic binding tape or rings on an aerial cable, a Industrial Drive Lexington, South Carolina Phone: Cables in this category may be applied in situations where the clearing time requirements of the percent level category cannot be met, and p-54-482 there is adequate assurance that the faulted section will be de-energized in a time not exceeding one hour.
Helically applied tape not overlapped. The following equation can be utilized to find the reactance of a given configuration by using the concept of geometric mean radius. For a typical 35kv cable with conductors in the — kcmil range, XLPE jackets may permit a 25 percent reduction in neutral wire copper content.
Every source I found used a different formula which does take the shield diameter into account. This diagram can be used to determine the reactance of any solid or concentric stranded conductor. If magnetic ducts must be used, it is recommended that all three cables be placed in a single duct. 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.
For example, the effective area of a composite shield consisting of a helically applied tape and kcea wire serving would be the sum of the areas calculated from Formula 2 or 3 and Formula 1.
The following table lists equations commonly used for determining various parameters of an electrical system where: These formulas are shown also in: This may be improved by using parallel circuits but is much further reduced by using insulated cable. Where the surface of cable collects conducting materials. The same considerations apply to exposed installations where personnel who may not be acquainted with the hazards involved handle cables. Single conductors should not be installed in individual magnetic conduit because of the excessive reactance.
This decreases the reactance to fault currents and increases human safety factor. Grounding of the Insulation Shield The insulation shield must be grounded at least at one end and preferably at two or more locations. XLPE’s higher abrasion-resistance can also reduce potential cable damage during installation. Use of Insulation Shielding The use of shielding involves consideration of installation and operating conditions.
The effective area of thin, helically applied overlapped tapes depends, also, upon the degree of electrical contact resistance of the overlaps.
For additional security, a mechanical device, such as a clamp, may be used to fasten the ends of the connection together.
Any input on how you calculate shield resistance would be appreciated. Installing a single cable in a magnetic duct results in HIGH reactance and a de-rated ampacity.
The formula you picked up from P is destined for: 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. Corrugated tape, longitudinally applied.
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The formula also seems to imply that the shield resistance is independent of the ucea of the shield, p–45-482 seems wrong to me. Consult the cable manufacturer for insulation thicknesses.
Close this window and log in. Voltage regulation is often the limiting factor in the choice of either conductor or type of insulation. The effective area of composite shields is the sum of the effective areas of the components. Are you an Engineering professional?
Formula 3 may be used to calculate the effective cross-sectional p-45-82 of the shield for new cable. An insulation shield has p4-5-482 number of functions: Transition from moist to dry earth. This combination will ensure a permanent low resistance, which will maintain contact even if the solder melts. Functions of Shielding A strand shield is employed to preclude excessive voltage stress on voids between conductor and insulation. This can simplify application engineering.
The percent voltage drop is the same between conductors as from conductor to ground and should not be multiplied by 3.
Shield Materials Two distinct types of materials are employed in constructing cable shields: