SIW: types, characteristics and differences

  • Dec 26, 2019

SIP - it is self-supporting insulated wire, which is used to connect private homes to industrial networks. The design assumes binding wire insulation three wires (phase) and an uninsulated open conductor which is used as a "scratch". CIP is fastened on special anchors or supports, and at the time of installation a little stretched.

Figure 1: Standard CIP
Figure 1: Standard CIP

Advantages and SIP variants

SIP - this wire, which is used exclusively for connecting homes and other buildings, mostly residential applications.

Its advantages are as follows:

  • Due to the insulation of the phase conductors is not possible undesirable crossing of wires and a short circuit.
  • Open seal minimizes the chances of illegal connections.
  • wire design is very convenient, which allows for quick and reliable installation.

SIP has several varieties, is strictly regulated by GOST 31946-2012:

  • STS-1 - standard cable for open laying with three insulated conductors and one bare.
  • SIP-2 - all four conductors insulated.
  • SIP-3 - in addition to the insulation of the wires, an additional protective casing. STS-3 is often used for voltage 6-35 kV lines.
  • SIP-4 - does not include the fourth conductor. Such wire is manufactured only sections 16 and 25 mm2.
  • GHGIS - further coated with a sealant, thereby eliminating the undesirable effects of oxygen.
  • SIPn - wire which does not support combustion, and the temperature is raised slowly begins to decay.
Figure 2: SIP Enter into a private house
Figure 2: SIP Enter into a private house

Insulated conductors is polyethylene, polyvinyl chloride and not, as in the wire and cable for wiring inside buildings. The carrier core (zero without isolation) is made of aluminum instead of copper.

Dimensions of LV

Virtually all of its varieties of SIP specifications are identical. Can change only the presence of insulation and conductors.

Specifications SIP:

  1. Operating voltage: 1 kV is applied to 1, 2, 4 and 5 categories, from 1 to 35 kV - 3 applied category.
  2. Number of cores - 3 or 4 (STS-3 has a single strand).
  3. Cross section - from 16 to 240 mm2.
  4. Allowable operating temperature - 90 C.
  5. Type of insulation - thermoplastic and light-stabilized polyethylene.
  6. Ambient temperature - from -60 C to +50 C.
  7. Declared by the manufacturer service life - not less than 40 years.

Because the aluminum bearing core wire bend radius is not less than 10 outer diameters.

Proper CIP gasket

Transport of SIP should be done as carefully as possible so as not to damage the insulation. During the installation do not unwind the cable on the ground, and try not to catch him by the branches of the trees.

SIW is mounted only on special rollers made of plastic. Previously used ceramic insulators, but now the technology is considered obsolete. With piercing connectors very easy to make branches without breaking isolation as conductors, and a zero (eg, SIP-2).

Figure 3: Correct mounting CIP on a pole
Figure 3: Correct mounting CIP on a pole

Between an insulated conductor fixed SIP nylon ties. Anchor clamp holds the wire in a small stretch, as further secured to the anchor bracket mounted on the column. Anchor bracket in turn is attached to a post by means of steel bands tightened straps.

STS has established itself as a reliable and durable wire and is in demand in almost all master electricians. Another positive thing - affordable price CIP policy, which is important when you connect at home.