RADIO DANGERS

Poverty Bay Herald, Volume LII, Issue 16228, 30 December 1926, Page 3

RADIO DANGERS

INSURANCE AFFECTED AERIAL PROTECTION The installation of u radio receiving set in a house has ati important bearing on the lire insurance policy Of the occupier, both in regard to the house itself and the furniture. There is an obligation on tho occupier to notify the insurance company of the installation so that, if necessary, the underwriters' electrical expert way examine the wiring, states an exchange. Rules have been issued by Uic Council of the Fire .and Accident .Underwriters' Associations of New Zealand covering the installation of sets, and these must be adhered to, as a breach of them is liable to make the policy Void. Those rules are simple, and by following them a good aerial-earth system is obtained. The rules state that aerials must not cross over, or under electric, light; or power lines, and they must be so constructed that a failure of either tho aerial or the electric light lines will not result in a contact between them. Splices and joints in the aerial system, unless made with approved clamps or splicing devices, must bo soldered. These conditions do not apply to indoor aerials. In a note to the rules concerning aerials the Council states that the size of the aerial will depend on the span. For the ordinary receiving set an aerial of about 100 ft long is recommended. As to the wire, the Council recommends that No. It gauge soft drawn copper wire or other wire of equal strength bo used. LEAD-IN WIRES Dealing with lead-in wires, the regulations stato that they shall be of copper, approved copper-clad steel, or other approved metal which will t not corrode excessively. In no case shall they be smaller than No. 14 standard wire gauge, except that approved cop-pcr-elad steel wire of not less than No. 17 standard wire gauge may be used. Lead-in wires are prohibited from coming nearer to electric light or power lines than 12in., unless separated by a continuous and firmly-fixed non-conductor that will maintain permanent separation. The insulation of the wiro is not a sufficient non-conduc-tor. A further clause states that lead-in wires shall enter a building through •a non-combustible, non-absorptive insulating bushing. Tho only portion of the lead-in wiro whieh needs to be insulated is the portion which' passes through the wall of a building, this being required in order to prevent possible earthing through coming into contact with metal concealed in the walls. LIGHTNING ARRESTERS An approved lightning arrester which will operate at a potential of 500 volts or less is 'required bv the regulations. This is to be installed as near as practicable to where ihe wire enters the building. It must not be placed in tho immediate vicinity of easily ignitable material or where' exposed to gases, dust or flyings of combustible material. The use of an antennae grounding switch is desirable, but it does not obviate tho necessity for a lightning arrester. If the switch is installed, it must, in its closed position, form a, (Shunt around the lightning arrester. , In a note to this section the regulations state that cheap home-made devices' should be discouraged. Fuses are not. required, but if installed should be between (he lead-in and the lightning arrester. PROTECTIVE GROUND WIRE, The earth front the lightning arrester may be bare or insulated, and must be of copper or approved copper* clad steel. In the case of wire it must not be smaller than No. 14 standard wire gauge, or in the case of 'copper clad, of No. .17 s.w.g. The' earth must be run in a straight line, as far us possible, to a good 'pernio pent earth. Preference is giveu to water piping, and gas piping is prohibited. Driven pipes, plates and cones arc allowed. When connected to pipes the earth must be attached by an approved clamp.

•Wires inside buildings are not permitted to come closer than two inches to electric light or power lines. Porcelainy or approved flexible' tubing, may be used to keep the wires away from electric lines.