ICEA P-45-482 PDF
September 18, 2019 | by admin
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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Where non-shielded non-metallic jacketed cables are used in underground ducts containing several circuits, which must be worked on independently, the external field if sufficiently intense can cause shock to those who handle ciea contact energized cable. More specific information on requirements for shielding by cable type is provided in the following table.
Where regulation is an important consideration several factors should be kept in mind in order to obtain the best operating conditions. Various modifications are necessary for use under special conditions is covered in notes on the nomogram. Cables in this category may be applied in situations where the clearing time requirements of the percent level category cannot be met, and yet there is adequate assurance that the faulted section will be de-energized in a time not exceeding one hour.
Shielding used to reduce hazards of shock should have a resistance low enough to operate protective equipment in case of fault. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.
Students Click Here Join Us! The area of contact should be ample to prevent the current from heating the connection and melting the solder.
This combination will ensure a permanent low resistance, which will maintain contact even if the solder melts. To reduce the hazard of shock. 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.
General Calculations Excerpt from PRYSMIAN`S WIRE AND CABLE
Single conductor including assemblies of single conductors a. Wires applied either helically, as a braid or serving; or longitudinally with corrugations. The system short circuit capacity, the conductor cross-sectional area and the circuit breaker opening time should be such that these maximum allowable short circuit currents are not exceeded.
Now to find out why Prysmian isn’t following their own guide While resulting in slightly higher reactances iceea three cables in a non-magnetic duct, it is optimal relative to the alternative of a single cable in a magnetic duct.
As a guide in preventing such serious damage, maximum allowable short circuit temperatures that damage the insulation to a slight extent only, Industrial Drive Lexington, South Carolina Phone: Close this window and log in. The formula also seems to imply that the shield resistance is independent of the diameter of the shield, which seems wrong to me.
Stress cones should be made at all shield terminations. Functions of Shielding A strand shield is employed to preclude excessive voltage stress on voids between conductor and insulation. The shield should operate at or near ground potential at all times. The formula you picked up from P is destined for: I came up with 7. From the attached sketch one may calculate the resistance as following: So, A is not an actual area-in order to calculate the tape resistance.
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General Calculations Excerpt from PRYSMIAN`S WIRE AND CABLE
XLPE jackets promise sustainability benefits including: Dry soil, such as in the iicea. If magnetic ducts must be used, it is recommended that all three cables be placed in a single duct. The percent voltage drop is the same between conductors as from conductor to ground and should not be multiplied by 3.
An increase in contact resistance may occur after cable installation, during service exposed to moisture and heat. XLPE’s higher abrasion-resistance can also reduce potential p-45-842 damage during installation. It covers spacing encountered for conduit wiring as well as for open wire circuits. The maximum short-circuit current that can flow in a given shield or sheath for a given time, or 3. XLPE jackets promise sustainability benefits including:.
Using a mechanical clamp such as a constant tension spring or a hose clamp is usually adequate to secure the connection. Helically applied tape not overlapped. Connection to aerial lines.
The effective area icfa thin, helically applied overlapped tapes depends, also, upon the degree of electrical contact resistance of the overlaps. In this connection it should be remembered that the high voltage circuit should be carried as far as possible so that the secondary runs, where most of the p-45-428 drop occurs, will be small. Higher allowable temperatures mean that a smaller number of neutral wires can carry the same short-circuit current.
Shield losses due to circulating currents go down by approximately 2 percent, which brings energy costs down. For additional security, a mechanical device, such as a clamp, may be used to fasten the ends of the connection together.
It’s easy to join and it’s free. Thank you 7anoter4 for your detailed response. Inductive Reactance to Neutral The following is a nomogram used to determine the inductive reactance of solid or stranded concentric conductors at 60 Hz.
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: Open wire lines have a high reactance. It accommodates various spacing of the conductors and other unique parameters as indicated within the nomogram itself.
Auxiliary nonmetallic conducting shields may adhere to the insulation, so that the use of a grit aluminum oxide cloth or similar material may be required to assure removal of the conducting material from the insulation surface See pages 28 – 30 for generalized discussion of cable preparation for splicing and terminating.
Consult the cable manufacturer for insulation thicknesses. All grounding connections should be made to the shield in such a way as to provide a permanent low resistance bond. The following equation can be utilized to find the reactance of a given configuration by using the concept of geometric mean radius. Three conductors in the same conduit have pp-45-482 lower reactance than conductors in separate conduits.