Office wire has the two cotton layers braided, the inside one being filled with a moisture-repelling compound.
Both office and annunciator wires have their outside coverings filled with paraffin and highly polished.
From the ease with which annunciator wire is stripped of its cotton covering, the braided office wire is to be preferred. These coverings are made in a variety of colors.
Weatherproof covered wire is mostly used for electric light work, but the sizes given above are good for bell work, although their larger outside diameter makes them harder to conceal.
The approximate number of feet to the pound of office and annunciator wire is given in the table.
| Office Wire. | Annunciator Wire. | ||
| No. | Feet per lb. | No. | Feet per lb. |
| 12 | 35 | 18 | 180 |
| 14 | 55 | 20 | 225 |
| 16 | 95 | ||
| 18 | 135 | ||
Joints.
Upon the care with which a joint is made much depends, a loose or poorly made joint will offer much resistance to the current.
The correct way to start a joint in annunciator, or office, wire is shown in [Fig. 22]. About three inches of each wire to be joined is bared of its insulation and scraped bright. The ends are then bent at right angles to each other, hooked together and one end firmly twisted around the other, as shown in [Fig. 23]. Any projecting pieces are cut off, and the joints should then be soldered to prevent corrosion.
