Standard Electrical Porcelain

(from Jack Tod's book: The History of the Electrical Porcelain Industry in the United States)

 

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Standard Porcelain Styles (Drawings)

Specialty Porcelain

 

The very rapid growth of the electrical power industry in the 1890's inevitably led to a rapid state of confusion regarding acceptable methods of electrical construction and the forms of electrical apparatus turned out by a very large number of manufacturers. This randomness of material specifications and installation methods not only became a factor in the increased incidences of electrical shocks and fires, but it was creating a staggering variety of manufactured electrical equipment, especially the insulators and wire used for over-surface wiring inside buildings.

 

Naturally the ones most concerned with these problems were the fire insurance companies, and they were the first to act. The National Board of Fire Underwriters founded the Underwriters' Laboratories, Inc. in 1894 to formulate safety standards for the industry. Up to modern times there have been numerous agencies and national associations involved with these matters, and it is beyond the scope of this book to detail the history of the various standards and codes which have evolved.

 

The National Electrical Code was first published in 1897 as a result of a national conference of engineering and underwriters' organizations, and it has been periodically revised and expanded throughout the years. The Code was initially a set of rules relating to electrical installations and which were intended to prevent fire hazards, and one major section of the Code set forth standards for the materials, fittings and details of their use in electrical construction. Of interest to us here are the standards for porcelain insulators used for over-surface wiring.

 

The initial effect on insulators for house wiring was to standardize the forms of two-wire cleats and tubes then in use for this purpose. The standards subsequently included minimum specifications for nail knobs as they came into wide use a few years later. Of primary importance from the standpoint of fire and electrical shock were spacing of the conductors from the mounting surface and from the nail or screw used to secure the insulator. Eventually the standards even spelled out other dimensions of the insulators not involved with those factors.

 

Standards were also set for two other large classes of insulators which were used for surface wiring in structures other than residences.  These were one-wire cleats and all forms of solid knobs. It might seem that only a small variety of insulators would be involved once standards were created, but this was not the case. Cleats had to be made for very large numbers of different conductor sizes and for varying electrical and mechanical loading factors. Knobs had to be made for an equally large number of different applications. Even at that, the Code did put a stop to the unrestrained growth of a myriad of insulator styles manufacturers were turning out.

 

It was fortunate that the standards were adopted as early as they were in the industry. This was before the super boom period in electrical wiring got underway. The manufacturers involved early in the game had to make only slight changes in their products, since most of the cleats and knobs made in any quantity were essentially included with only very minor changes in the standard porcelain charts. Companies entering the porcelain insulator business after the adoption of the Code made products which complied with the standards.

 

Not surprisingly, all the porcelain insulators used for surface wiring soon came to be known as "Standard Porcelain", and many manufacturers restricted their activities to these items. Most of the very small companies coming upon the scene in boom times made only the high-volume house wiring insulators, and the larger companies made more extensive lines of standard porcelain. Catalogs of several of the larger manufacturers had listings for virtually every size and style of standard cleats, knobs and tubes. In the case of cleats and knobs, this involved a tremendous number of dry press dies in their tooling department. In the case of tubes, it created a very large inventory of finished products. Even with porcelain insulators fairly standardized, it must have been a chore for jobbers and distributors to handle the large variety.

 

As differentiated from "Standard Porcelain", all porcelain insulator products not included in the standards became known as "Specialty Porcelain". Except for the very small nail knob companies in the super boom, nearly all electrical porcelain manufacturers made specialty porcelain to varying degrees, even if their main product was standard porcelain. This specialty porcelain was occasionally a proprietary product, but generally it was made on contract for other electrical manufacturers.

 

Manufacturers of standard porcelain tended to follow the Code in the more important features such as overall insulator size, hole diameter, groove size, etc. Standard knobs and cleats by various manufacturers did vary with regard to unimportant details such as crown curvature, beveled corners, base counterbore shape, etc. There was also some discrepancy on outline dimensions and numbering methods used by various companies. For instance, some companies list the #3-1/2 knob as a #3 W.G. (wide groove).

 

The Standard Porcelain chart for solid knobs is shown on the following pages. There was one major revision of the knobs in the Code wherein some items were deleted, others added, dimensions of some changed, Sizes shown are generally for the New Code (N.C.), but both sizes are shown for the #5-1/2 (which is the proverbial nail knob in split form, 5-1/2-split). The chart is nominally for solid knobs, but split knobs normally used as forestry insulators are also shown; these are the Victor #22, #37-Split and #38-Split.

 

As you can see, there was a "standard" knob for virtually every use. It would be interesting to know just what pull some manufacturers had to get obviously proprietary knob designs included in the Code -- notably the #17, #18, #35 and the electric fence items #57 and higher. Some of the numbers were commonly used in many types of wiring installations, but others were probably made for rather limited applications.

 

 

 

Click on the photo above to see a larger photo.  The collection as shown contains 228 insulators and are listed below.  Detailed photos of each insulator is shown in the 8 pages of photos.

 

The table below shows the various standard porcelain in my collection.  The first number is the Standard Porcelain number.  The number after the dash is a sequence number.  To review a drawing for the Standard Porcelain style, go here: Standard Porcelain Drawings.  To see a photo of a specific insulator, click on the Number or go here: Standard Porcelain Photos.

 

emb: embossed

r-e: recess-embossed

u-g: under-glaze ink

/ : marking on opposite side

// : marking on bottom

 

No.   MARKING Marking Type Color Company Notes
0-01 N-N    white    
0-02 R T & S CO emb white R. Thomas & Sons Co.  
             
½-01 N-N   white    
             
1-01 BRUNT emb white G. F. Brunt Porcelain Co.  
1-02 MACOMB emb white Illinois Electric Porcelain Co.  
1-03 PP-1 incuse white Porcelain Products Co.  
1-04 O. P. CO. emb white    
1-05 R T & S CO emb white R. Thomas & Sons Co.  
1-06 PERU emb white Peru Electric Porcelain Co.  
1-07 Triangle M / 1 emb white Illinois Electric Porcelain Co.  
1-08 T r-e white R. Thomas & Sons Co.  
1-09 A. P. CO. emb white Anderson Porcelain Co.  
1-10 F emb white Findlay Electric Porcelain Co.  
1-11 R. P. Co. emb white Ravenswood Porcelain Co.  
1-12 FEDCO emb white Federal Porcelain Co.  
1-13 KNOX / 1 r-e white Knox Porcelain Corp.  
1-14 G emb white ??  
1-15 T.P. (on bottom) r-e white Trenton Porcelain Co.  
1-16 E emb white East Liverpool Electrical Porcelain Co.  
1-17 S P (bottom) emb white Superior Porcelain Co.  
             
2-01 P. P. INC. / 2 emb white Porcelain Products Inc. flat top and flat bottom
2-02 PERU emb white Peru Electric Porcelain Co. short
2-03 R T & S CO emb white R. Thomas & Sons Co. tall
2-04 P. P. INC. / 2 emb white Porcelain Products Inc. round top and recessed bottom
2-05 N-N   white    
2-06   Triangle M // 2 emb // r-e white Illinois Electric Porcelain Co.  
2-07 E emb white East Liverpool Electrical Porcelain Co.  
2-08 PERU emb white Peru Electric Porcelain Co.  
2-09 US incuse white U.S. Electric Porcelain Co.  
             
3-01   F (top) // F (btm) emb white Findlay Electric Porcelain Co.  
3-02 N-N   white    
3-03 THOMAS emb white R. Thomas & Sons Co.  
             
3½-01 P P / -2 emb white Porcelain Products Inc.  
3½-02 U S (intertwined logo) emb white U.S. Electric Porcelain Co.  
3½-03 F // F E P Co (around bottom) emb white Findlay Electric Porcelain Co.  
3½-04 F // F E P Co (around bottom) emb brown Findlay Electric Porcelain Co.  
3½-05 G P Co. / 3½ emb white    
3½-06 Triangle M emb white Illinois Electric Porcelain Co.  
3½-07 No. 3½ / DIEN01 (all markings on bottom) emb white ??  
3½-08 P. P. Inc. U.S.A. / 3½ emb white Porcelain Products Inc.  
3½-09 A. P. CO // 3½ emb white Anderson Porcelain Co.  
3½-10 E emb white East Liverpool Electrical Porcelain Co.  
3½-11 PERU emb white Peru Electric Porcelain Co.  
             
4-01 N-N   white    
4-02 T r-e white R. Thomas & Sons Co.  
4-03 N-N (short)   white    
4-04 N-N (shorter)   white    
4-05 R. T. & SON'S (bottom) emb white R. Thomas & Sons Co.  
4-06 N-N (different shape)   white    
4-07 Diamond (bottom) inc white Diamond Porcelain Co.  
4-08 SPCO (bottom) emb white Superior Porcelain Co.  
4-09 US (intertwined) emb white U. S. Electric Porcelain Co.  
4-10 N-N   white   deep cone bottom
4-11 UPW and eagle head u-g ink white Union Porcelain Works flat bottom
4-12 N-N   white    
4-13 N-N   gray    
4-14 N-N   white    
4-15 HF (bottom) emb white Hartford Faience Co.  
4-16 F. P. CO. emb white Franklin Porcelain Co.  
4-17 UPW and eagle head u-g ink white Union Porcelain Works recessed bottom
4-18 A.P. CO. emb white Anderson Porcelain Co.  
4-19 BRUNT emb white G. F. Brunt Porcelain Co.  
             
4½-01 E emb white East Liverpool Electrical Porcelain Co. small
4½-02 N-N   white    
4½-03 E. P. (bottom) emb white Electrical Porcelain Co.  
4½-04 T r-e white R. Thomas & Sons Co.  
4½-05 N-N   white   cone top
4½-06 G emb white ??  
4½-07 GLOBE emb white Globe Porcelain Co.  
4½-08 FEDCO emb white Federal Porcelain Co.  
4½-09 SUPERIOR / No. 5½ emb white Superior Porcelain Co.  
4½-10 T // 1 r-e/emb white R. Thomas & Sons Co.  
4½-11 A I & M CO (bottom) emb gray Akron Insulator & Marble Co.  
4½-12 E emb white East Liverpool Electrical Porcelain Co.  
4½-13 M emb white Illinois Electric Porcelain Co.  
4½-14 N-N   white    
4½-15 T r-e white R. Thomas & Sons Co. larger
4½-16 T r-e white R. Thomas & Sons Co. smaller
4½-17 F (bottom) emb white Findlay Electric Porcelain Co.  
4½-18 G emb white ?? smaller
4½-19 A M C (bottom) emb white American Marble & Toy Mfg. Co.  
             
5-01 SUPERIOR / 5 emb white Superior Porcelain Co.  
5-02 P. P. INC. / 5 / U.S.A. / 5 (in a circle) emb white Porcelain Products Inc.  
5-03 A M C (bottom) emb white American Marble & Toy Mfg. Co.  
5-04 N-N   white   flat on bottom
5-05 N-N   white   cone top, recessed bottom
5-06 N-N   white   deep cone bottom
5-07 BRUNT emb white G. F. Brunt Porcelain Co.  
5-08 N-N   white   larger
5-09 P P INC emb cobalt blue Porcelain Products Inc.  
5-10 F (bottom) emb white Findlay Electric Porcelain Co.  
5-11 WIS-P-C. / USA emb white Wisconsin Porcelain Co.  
5-12 WP / 5 / USA emb white Wisconsin Porcelain Co.  
5-13 A M C (bottom) emb gray American Marble & Toy Mfg. Co.  
5-14 A M C (bottom -with blue stripe) emb gray American Marble & Toy Mfg. Co.  
5-15 Triangle M r-e white Illinois Electric Porcelain Co.  
             
5½-01 U / 5½ r-e white Universal Clay Products Co.  
5½-02 ??   white    
5½-03 P / 5 (bottom) emb white    
5½-04 CANTON (bottom) emb white ??  
5½-05 P / 5 (bottom) emb white    
5½-06 SUPERIOR / 5½ emb white Superior Porcelain Co.  
5½-07 P & S (on side) emb white Pass & Seymour, Inc.  
5½-08 BRUNT emb white G. F. Brunt Porcelain Co.  
5½-09 P. P. INC. / 62 / U.S.A. / 5½ (circle) emb white Porcelain Products Inc.  
5½-10 KNOX / 5½ r-e white Knox Porcelain Co.  
5½-11 T r-e white R. Thomas & Sons Co.  
5½-12 T r-e white R. Thomas & Sons Co. larger
5½-13 Triangle M / 5½ r-e white Illinois Electric Porcelain Co.  
5½-14 US (intertwined) emb white U.S. Electric Porcelain Co.  
5½-15 P. P. INC. / 5½ emb white Porcelain Products Inc.  
5½-16 F (bottom) emb white Findlay Electric Porcelain Co.  
5½-17 Diamond (bottom) incuse white Diamond Porcelain Co.  
5½-18 E emb white East Liverpool Electrical Porcelain Co.  
5½-19 THOMAS emb white R. Thomas & Sons Co.  
5½-20 HP / B (bottom) emb white Akron High-Potential Porcelain Co.  
5½-21 KNOX / 5½ r-e white Knox Porcelain Co. different marking than 5½-10
5½-22 THOMAS emb white R. Thomas & Sons Co.  
5½-23 P. S. CO. emb white    
5½-24 JIM // BROWN emb white    
5½-25 SUPERIOR / 5½ emb brown Superior Porcelain Co.  
5½-26   A M C (bottom) emb white American Marble & Toy Mfg. Co.  
             
6-01 F emb white Findlay Electric Porcelain Co.  
6-02 BRUNT emb white G. F. Brunt Porcelain Co.  
6-03 S. P. Co. / 6 emb white Superior Porcelain Co.  
6-04 T (bottom) r-e white R. Thomas & Sons Co.  
             
7-01 N-N   white    
7-02 ??   white    
7-03 SUPERIOR / No. 7 emb white Superior Porcelain Co.  
7-04 N-N   white    
7-05 N-N (Thomas)   white R. Thomas & Sons Co.  
             
8-01 N-N (Findlay)   white Findlay Electric Porcelain Co.  
             
9-01 N-N   white   cone bottom
9-02 N-N   white   flat bottom
             
10-01 BRUNT emb white G. F. Brunt Porcelain Co.  
10-02 THOMAS (bottom) emb white R. Thomas & Sons Co.  
             
11-01 BRUNT emb white G. F. Brunt Porcelain Co. cone bottom
11-02 A M C emb white American Marble & Toy Mfg. Co.  
             
12-01 F emb white Findlay Electric Porcelain Co. F parallel to side
12-02 F emb white Findlay Electric Porcelain Co. F perpendicular to side
12-03 G. P. Co. emb white General Porcelain Co.  
12-04 THOMAS emb white General Porcelain Co.  
             
13-01 F emb white Findlay Electric Porcelain Co.  
             
14-01 N-N   white    
14-02 S. P. CO. (bottom) emb white Superior Porcelain Co.  
14-03 Triangle M emb white Illinois Electric Porcelain Co.  
             
15-01 PERU emb white Peru Electric Porcelain Co.  
15-02 F emb white Findlay Electric Porcelain Co.  
             
16-01 N-N   white    
16-02 U (bottom) r-e white Universal Clay Products Co.  
16-03 WP6 / U.S.A. r-e white Wisconsin Porcelain Co.  
16-04 N E T & T r-e white New England Telephone & Telegraph Co.  
16-05 U.S.A. / U.S.A. emb white    
16-06 HP / P / S / 55 (bottom radially) r-e white    
16-07 KNOX / 7138-S r-e white Knox Porcelain Co.  
16-08 T (bottom) r-e white R. Thomas & Sons Co.  
16-09 U.S.A. (bottom) r-e white    
16-10 N. E. T. & T. CO. r-e white New England Telephone & Telegraph Co.  
16-11 T r-e white R. Thomas & Sons Co.  
             
18-01 N-N   white    
             
19-01 DAVIS & WATTS / BALTO emb white    
             
20-01 N-N emb white   very rounded
20-02 P. P. INC. / NO. 20 emb white Porcelain Products Inc.  
20-03 F emb white Findlay Electric Porcelain Co.  
20-04 MACOMB emb white Illinois Electric Porcelain Co.  
20-05 Triangle M emb white Illinois Electric Porcelain Co.  
20-06 R. T. & S. CO. emb white R. Thomas & Sons Co.  
20-07 Triangle M emb cobalt blue Illinois Electric Porcelain Co.  
             
21-01 N-N (Thomas)   white R. Thomas & Sons Co.  
             
22-01 N-N   white    
             
23-01 N-N   white   recessed bottom
23-02 N-N   white   flat bottom, skinny
23-03 N-N   white   flat bottom
23-04 F (bottom) emb white Findlay Electric Porcelain Co. tall
23-05 N-N   white   very rounded
23-06 F (bottom) emb white Findlay Electric Porcelain Co. short
23-07 N-N (Colonial)   white   flat bottom
23-08 N-N   gray    
23-09 N-N   white   very rounded, like 23-05, no mold lines
             
24-01 S# 145458 (bottom) r-e brown ??  
24-02 F emb white Findlay Electric Porcelain Co.  
24-03 N-N (S. P. Co.)        
24-04 A M C (bottom) emb pottery Akron Marble Co.  
24-05 PERU emb white Peru Electric Porcelain Co.  
24-06 R T & S CO // R T & S CO emb white R. Thomas & Sons Co.  
24-07 Triangel M emb white Illinois Electric Porcelain Co.  
24-08 THOMAS emb mustard brown R. Thomas & Sons Co.  
24-09 MACOMB emb white Illinois Electric Porcelain Co.  
24-10 N-N   chocolate brown   3 firing teats on bottom
24-11
 
P.P. U.S.A. / NO. 24. emb white Porcelain Products Inc.  
             
25-01 F emb white Findlay Electric Porcelain Co.  
25-02 E P emb white Electrical Porcelain Co.  
             
26-01 PERU emb white Peru Electric Porcelain Co. smaller, small hole
26-02 PERU emb white Peru Electric Porcelain Co. larger, large hole
26-03 R T & S CO // R T & S CO emb white R. Thomas & Sons Co. smaller wire groove
26-04 R T & S CO // R T & S CO emb white R. Thomas & Sons Co. larger wire groove
             
29-01 MACOMB emb white Illinois Electric Porcelain Co. 2-part fused
29-02 F emb white Findlay Electric Porcelain Co. 2-part fused
29-03 BRUNT // BRUNT emb white G. F. Brunt Porcelain Co. 2-part fused
29-04 U.S.A. P. P. INC. / NO. 29 emb white Porcelain Products Inc. 2-part fused
29-05 A emb white ??  
29-06 N-N   white    
29-07   R T & S CO emb white R. Thomas & Sons Co. 2-part fused
29-08 O. P. Co. emb white Ohio Porcelain Co 2-part fused
             
30-01 THOMAS emb white R. Thomas & Sons Co.  
             
31-01 N-N (Globe)   white Globe Porcelain Co.  
31-02 NATIONAL NO. 31. r-e white National Metal Molding Co.  
31-03 THOMAS emb white R. Thomas & Sons Co.  
31-04 T r-e white R. Thomas & Sons Co.  
             
32-01 N-N   white    
32-02 PERU emb white Peru Electric Mfg. Co.  
             
35-01 N-N   tan    
35-02 N-N   white    
35-03 N-N   brown    
             
36-01 F emb white Findlay Electric Porcelain Co. smaller
36-02 N-N   white    
36-03 G emb white ?? lareger
36-04 KNOX / 36 r-e white Knox Porcelain Co.  
             
37-01 F emb choc brown Findlay Electric Porcelain Co.  
37-02 P. P. U.S.A. 37 (circle) emb white Porcelain Products Inc.  
37-03 R T & S CO // R T & S CO emb white R. Thomas & Sons Co.  
37-04 F emb white Findlay Electric Porcelain Co. narrow wire groove
37-05 E emb white East Liverpool Electrical Porcelain Co. wide wire groove
37-06 WP36 / USA r-e white Wisconsin Porcelain Co.  
37-07 USA (bottom) r-e white ??  
37-08 N-N        
             
37S-01

 

 R T & S CO emb white R. Thomas & Sons Co.  
37S-02

 

 PERU emb white Peru Electric Porcelain Co.  
             
39-01 F emb white Findlay Electric Porcelain Co. 2-part glazeweld
39-02 F emb gray Findlay Electric Porcelain Co. 2-part glazeweld, larger
39-03 39 emb white    
             
45-01 FINDLAY / 1925 emb white Findlay Electric Porcelain Co. small
45-02 F emb white Findlay Electric Porcelain Co.  
45-03 US emb white U.S. Electric Porcelain Co.  
45-04 FINDLAY / 1926 // F emb white Findlay Electric Porcelain Co.  
45-05 PP 1180 emb white Porcelain Products Inc.  
             
46-01 F emb white Findlay Electric Porcelain Co.  
             
47-01 CROSS/COUNTRY r-e brown    
             
48-01 T emb white R. Thomas & Sons Co.  
             
50-01 F emb white Findlay Electric Porcelain Co.  
             
51-01 N-N (G. P. Co.)   white General Porcelain Co.  
51-02 THOMAS // THOMAS emb white R. Thomas & Sons Co.  
51-03 MADE IN U.S.A / T51 // (repeated on bottom) r-e white R. Thomas & Sons Co.  
51-04 OB u-g ink white Ohio Brass  
             
57-01 PAT. NO. 108489. emb white Porcelain Products Inc. design patent 108,489
             
59-01 P. P. INC. / 58 / U.S.A. / 58 (circle) emb white Porcelain Products Inc.  
59-02 PRIME emb brown ??  
59-03 PRIME emb cobalt blue ??  
             
61-01 WP-23 / USA emb white Wisconsin Porcelain Co.  
61-02 S. P. Co. / No. 666 emb white Superior Porcelain Co.  
61-03 P. P. INC. / 61 / U.S.A. / 61 emb white Porcelain Products Inc.  
61-04 Sears / USA emb white Wisconsin Porcelain Co.  
61-05   WP 22 / USA emb white Wisconsin Porcelain Co.  
61-06 WP 23 / USA emb white Wisconsin Porcelain Co.  
             
61a-01 NET&TCO emb white New England Telephone & Telegraph Co.  
             
62-01 P P INC / 62 / U.S.A. / 5½ (circle) emb white Porcelain Products Inc.  
62-02 CROSS COUNTRY emb white ??  
62-03 N-N   white    
62-04 CROSS COUNTRY emb brown ??  

 

 

Standard Porcelain Styles (Drawings)

 

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