Novoid Compounds For Medium Voltage Cable Joints, Terminations & Cableheads

By Chris Dodds on 20th October, 2015

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A guide to the correct selection and specification of NOVOID Compounds on medium voltage cable systems.

Compounds are a high dielectric strength filler material used in terminations, cable heads, cable boxes and cable joints.

An ideal compound should be chemically inert, adhesive and tacky; have low melting point to permit flow into all unoccupied space before solidifying, low moisture absorption, low dielectric loss, high dielectric strength and high flash and fire point for personnel safety.

The selection of the proper compound for a particular installation depends upon:

1. Cable type and kind of insulation

2. Operating voltage and temperatures

3. Cable system elevation differentials (PILC cable only)

 

Types of Compound

NOVOID "A" is a medium soft asphaltic base compound recommended for use in most cable termination and cablehead (switch or box) installations at 38kV or below.

NOVOID "C" is a medium hard asphaltic base compound recommended for use in cable  termination and cableheads for application in hot climates or hot exposure at voltages up to and including 38kV.

NOVOID "X" is a hard resin-bas, oil insoluble compound recommended for use in cable terminations, cableheads and joints where migration of the cable-tape impregnant may be a problem. There are temperature limitations.

NOVOID #224 is a heavy polybutene base compound recommended for use in cable terminations, cableheads and joints for polyethylene and EPR insulated cables.

NOVOID "9A" is a very soft asphaltic base compound recommended for use in spreaderhead installations up to 38kV where the compound must be very fluid to rise up in lead or copper tubes. The lower part of the spreaderhead may be filled with Novoid "X' to provide a barrier to help prevent migration of the Novoid "9A" down into the cable.

NOVOID#219 is a medium viscosity oil recommended for use as a flushing compound" for building cable splices or cable terminating where such "flushing" is required. It may also be used as a filling compound in terminations and joints on solid type paper insulated cables where oil filled accessories are desired.

OZITE "B' is a medium soft asphaltic base compound recommended for use in terminations or cableheads.

Cable Compound Selector Chart

Type Of Cable Insulation	Compounds
	NOVOID A	NOVOID C	NOVOID X	NOVOID 224
Paper Insulated, Lead Covered P.I.L.C	Yes	Yes, Note 1	Yes, Note 2	No
Varnish Cambric, Lead Covered, V.C.L.C	Yes	Yes	Yes	No
Butyl Rubber I.I.R Type	Yes, Note 3	Yes, Note 3	No	No
Cross Linked Polyethylene X-L Poly	Yes	No	No	Yes
Ethylene Propylene Rubber E.P.R	Yes, Note 3	No	No	Yes
Hi-Molecular Weight Poly	No	No	No	Yes
Kerite Insulation Permashield Type	Yes	Yes	No	No
Note 1: For abnormal temperatures -30ºC (-22ºF) to above 40ºC (104ºF)
Note 2: Not recommended for terminations and cableheads operating above 15kV where temperature may fall below -12ºC (+10ºF), or 15kV and below, where temperature may fall below -24ºC (-10ºF). No temperature limitation for compound used in joints.
Note 3: Maximum pouring temperature 150ºC (302ºF)

 

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Category:  HV Cable Jointing & Terminating

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