CD 290-309

Saddle wire groove - Triple petticoat

CD 304/310

CD 304/310

Size: 228mm x 304mm (9" x 12")

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Years produced: c.1910s-1920s
Style (CD) scarcity: 6, 501-1,000 known
Intended use: High Voltage
Style / catalog number: Unknown
Number of unique insulators: 10
Notes: Based off the design of the CD 303/310. The CD 304/310 became a reality due to some design changes made to strengthen the neck of the insulator as under extreme conditions the tops were breaking. See this article for more info. Also check out the photos of them in use.

Primary Embossing = Embossing on the front of the insulator, usually is that manufacturers name or the customers name. No embossing units will be noted as NO EMBOSSING. Units with no name but with numbers or letters will be noted as NO NAME.

Examples:
HEMINGRAY
S.B.T.&.T.Co
NO NAME
NO EMBOSSING

EIN = Embossing Index Number is a standardized way to identify each unique embossing.

(FS) = Front Skirt
(RS) = Rear Skirt
(DO) = Dome
(CR) = Crown
(FC) = Front Crown
(RC) = Rear Crown
(BG) = Between Grooves
(FA ) = Front, Above wire groove
(FB) = Front, Below wire groove
(BE) = Base Embossed
(FU) = Front Umbrella
(RU) = Rear Umbrella
(FCE) = Front Center
(RCE) = Rear Center
(TE) = Top Ear
(TOP) = Top of Pinhole
/ = Next line of embossing

There are unique characteristics of the insulator that are not related to the embossing, but is worth noting.

Examples:
Factory molded brass bushing
Flaired skirt
MLOB = Mold Line Over Base
Waffle top
Wide saddle groove

Base = the bottom of the insulator. It is noted in the following standardized ways.

SDP = Sharp Drip Points
RDP = Round Drip Points
CB = Corrugated Base
SB = Smooth Base

= Insulator has been verified that exists
= Insulator has been verified that exists, but not listed in the "guide"
= Insulator has not yet been verified as existing
= Suspected error listing in the "guide" because listing does not match up with known manufacturing practices. Such as numbers and dots on an aqua insulator, or insulators listed with both factory molded brass bushing and without. Many do not come in both configurations and are listed as coming in both. Etc.

Color = The approximate color of the insulator. Due to manufacturing variations, insulators with the same color name maybe slightly different in actual appearance.

Primary Embossing EIN Embossing Special Features Base Color Verified?

HEMINGRAY

[010]

(FS) HEMINGRAY/PATENT MAY 2 1893 (CD 310 sleeve is unembossed)

SDP

Aqua

HEMINGRAY

[010]

(FS) HEMINGRAY/PATENT MAY 2 1893 (CD 310 sleeve is unembossed)

SDP

Aqua w/ Milk Swirls

HEMINGRAY

[010]

(FS) HEMINGRAY/PATENT MAY 2 1893 (CD 310 sleeve is unembossed)

SDP

Blue Aqua

HEMINGRAY

[010]

(FS) HEMINGRAY/PATENT MAY 2 1893 (CD 310 sleeve is unembossed)

SDP

Green

HEMINGRAY

[010]

(FS) HEMINGRAY/PATENT MAY 2 1893 (CD 310 sleeve is unembossed)

SDP

Green Aqua

HEMINGRAY

[010]

(FS) HEMINGRAY/PATENT MAY 2 1893 (CD 310 sleeve is unembossed)

SDP

Hemingray Blue

HEMINGRAY

[020]

(FS) HEMINGRAY/PATENT MAY 2 1883 (Note MAY 2 1883 date} (CD 310 sleeve is unembossed)

SDP

Aqua

HEMINGRAY

[020]

(FS) HEMINGRAY/PATENT MAY 2 1883 (Note MAY 2 1883 date} (CD 310 sleeve is unembossed)

SDP

Blue Aqua

HEMINGRAY

[020]

(FS) HEMINGRAY/PATENT MAY 2 1883 (Note MAY 2 1883 date} (CD 310 sleeve is unembossed)

SDP

Green

NO EMBOSSING

[010]

(No embossing) (Hemingray product)

SDP

Aqua

  • [010] - Blue Aqua

    HEMINGRAY

    [010]

    Blue Aqua

  • [020] - Green

    HEMINGRAY

    [020]

    Green

    Details

    True green examples are hard to find.

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