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What is meant by pull back effect when pulling in electrical cables in conduit?
Wiki User
∙ 9y ago
what is meant by pull back effect when pulling in electric cables in conduit
Wiki User
∙ 9y ago
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What is the IEE regulations on space factors in conduits and ducts?
This topic is covered in the IEE's On-Site Guide, a supplement to BS 7671:2008 Regulations for Electrical Installations.'Grouping' describes to the mutual heating effect of adjacent conductors. The effect of grouping acts to reduce the number of cables actually allowed into an enclosure because, as the number of circuits increases, the current-carrying capacity of the cables reduces -requiring the use of cables with larger cross-sectional areas! And using cables with larger cross-sectional areas may then require us to use larger-diameter conduit.In practice, this might also mean distributing the cables between, say, two smaller conduits (or by using a small trunking system).Guidance in this is provided by an equation called a space factor, where:space factor = [(csa of all cables)/(internal csa of conduit)] x 100 %...where the maximum permissible space factor is 40%. In other words, the area of the cables must not exceed 40% of the internal cross-sectional area of a conduit. The 60% empty-space requirement is intended to enable the dissipation of the heat produced by the current-carrying conductors grouped inside the conduit.
What are the three factors that effect the electrical parameters of a op-amp?
Supply voltage , temperature , frequency are factors that effect the electrical parameters of opamp
What are three electrical devices that utilise the effect of heating effect?
1) Bi metallic strip ,which acts as overload protection switch in electrical appliances. 2) Thermocouples, which use heat and cold effect to generate electricity. 3) Thremo resistor which change their resistance with a change in temperature.
What are the main effects produced by the flow of current in an electrical circuit?
There are three effects produced by an electric current:heating effectmagnetic effectchemical effect
What is the effect of frenkel schottky defect on elictrical conductivity?
Both Frenkel and Schotty defects improve the electrical conductivity of an ionic crystal.
What is the IEE regulations on space factors in conduits and ducts?
This topic is covered in the IEE's On-Site Guide, a supplement to BS 7671:2008 Regulations for Electrical Installations.'Grouping' describes to the mutual heating effect of adjacent conductors. The effect of grouping acts to reduce the number of cables actually allowed into an enclosure because, as the number of circuits increases, the current-carrying capacity of the cables reduces -requiring the use of cables with larger cross-sectional areas! And using cables with larger cross-sectional areas may then require us to use larger-diameter conduit.In practice, this might also mean distributing the cables between, say, two smaller conduits (or by using a small trunking system).Guidance in this is provided by an equation called a space factor, where:space factor = [(csa of all cables)/(internal csa of conduit)] x 100 %...where the maximum permissible space factor is 40%. In other words, the area of the cables must not exceed 40% of the internal cross-sectional area of a conduit. The 60% empty-space requirement is intended to enable the dissipation of the heat produced by the current-carrying conductors grouped inside the conduit.
Can you have only one current carrying conductor in a conduit?
You can have only one current carrying conductor in a conduit, but that conduit must have a slot to relieve the eddy currents that will be created by the transformer effect created by the conductor. It is better to run the neutral or opposite conductor along with the hot conductor together in the same conduit, or through the same penetration, so as to minimize this effect.
Will oil effect an electrical connector?
no oil dos not effect an electrical connector
What is formula for calculate size of cable?
CABLE and WIRE are not the same thing.Cables are sized by the diameter of the longest side (romex isn't round, it's an oval, compared to CAT 5, which is round)Wires are sized based on the type of insulation and gauge of copper.Then you take that info to the code book. A chart tells you the answer. BEWARE: multiple cables or wires in a conduit changes the equation.Whether or not more will fit, the only correct way to size cables or wires is to use the Code Book.For UK InstallationsThis topic is covered in Appendix 5 of the On-Site Guide supplement to BS 7671:2008 Requirements for Electrical Installations (the 'IEE Wiring Regulations'), although this Appendix only relates to the ease with which cables can be drawn in, and does not take into account the effect of 'grouping' (i.e. the effect that the temperature of each conductor will have on the rest). The number of cables permitted depends upon (1) the total cross-sectional area of all the cables drawn in, (2) the length of run, and (3) the presence of bends.The effect of 'grouping' is to reduce the number of cables actually allowed within a conduit (or other enclosure), because, as the number of circuits increases, the current-carrying capacity of the cables reduces. Guidance on this is provided through 'space factor', which is the ratio of the (total csa of all the cables) to (the internal csa of the conduit), expressed as a percentage, with the maximum permissible space factor being 40%. The remaining 60% space is required to allow the dissipation of heat from the cables. (As the first answer indicates, the csa of a flat cable is based on the maximum width of that cable).
What will be the effect if the threaded portion of conduit is not fully fitted to the coupling?
In the United States, the NEC requires that runs of conduit be continuous and connections be made wrench tight. If done properly this provides added grounding protection to your circuits. If a connection is left loose, that added grounding protection does not exist. There are times when threaded connections simply won't thread completely. This may require that the conduit threads be "run" with a threader to remove whatever is preventing this from happening. With experience you learn what is acceptable or not acceptable. Generally, if the connection is "wrench tight" and is otherwise secure, that is sufficient.
Does pulling out sperm effect growth in teens?
it effects
What has the greatest pulling effect on the tides?
On Earth it's the moon.
What are the three factors that effect the electrical parameters of a op-amp?
Supply voltage , temperature , frequency are factors that effect the electrical parameters of opamp
By pulling in your belly can you lose your child during pregNancy?
No that wont effect it.
What is caused by the earth pulling down on you?
Your weight, caused by the effect of gravity.
How long does the effect of a electrical signals the effect of chemical signals tend to last?
Nerve impulses are electrical whereas hormones are chemical. Compared to the effects of electrical signals chemicals are slower to act and last for a long time
When paralleling a service must the sets of conductors be in separate conduits or can they be in the same conduit?
They can be either separated or combined. What governs the choice is the size of the service and the conductors feeding the service and the ability to physically connect metering equipment to larger size conduits. When paralleling conduits make sure all the phase wires are in their individual conduits to cancel the field effect of the wires. Eg. conduit 1 - L1 + L2 + N , conduit 2 - L1 + L2 + N. Likewise with three phase, conduit 1 - L1, L2, L3, conduit 2 L1, L2, L3.
