Two class letters
The first is the range: g full (overload and short circuit), a partial (short circuit only). The second is the use: G general, M motors, R semiconductors.
Reference tool — not a protection study
Read the fuse link before it goes in an RFQ.
Fuse link
Colour or marking.
Pick the indicator colour, or switch to the marking, where an offered replacement can be checked too: size, class, current, voltage and breaking capacity. The drawing and the RFQ line update with every change.
Examples:
Replacement check
On the markings alone: the link’s data sheet and the circuit it protects decide.
All 130 engineering tools
A fuse link carries its type and size, its class (gG, aM…), the rated current, the voltage and the breaking capacity; on Diazed and Neozed screw links the indicator colour shows the current too. Pick the colour or type the marking, and the reader decodes it and writes the RFQ line.
Decoding is not protection design: discrimination and cable sizes are the electrician’s to check against the drawings.
How a fuse link is read
Class, size, current.
Indicator colour
On screw links the colour of the dot shows the current: green 6 A, red 10 A, grey 16 A, blue 20 A, yellow 25 A.
Size and thread
Diazed DII is E27, DIII E33; Neozed D01 is E14, D02 E18, D03 M30 × 2. NH blade links go by size, cylindrical links by diameter and length.
| Current | Colour | Size (thread) |
|---|---|---|
| 2 A | Pink | DII (E27), D01 (E14) |
| 4 A | Brown | DII (E27), D01 (E14) |
| 6 A | Green | DII (E27), D01 (E14) |
| 10 A | Red | DII (E27), D01 (E14) |
| 16 A | Grey | DII (E27), D01 (E14) |
| 20 A | Blue | DII (E27), D02 (E18) |
| 25 A | Yellow | DII (E27), D02 (E18) |
| 32, 35, 40 A | Black | DIII (E33), D02 (E18) |
| 50 A | White | DIII (E33), D02 (E18) |
| 63 A | Copper | DIII (E33), D02 (E18) |
The 80 and 100 A colours are not given: the sources do not confirm them twice. NH blade links are read by size name: the sources give different current ranges per size.
Sources
Indicator colours and screw fuse sizes: Bussmann’s "D Diazed and DO Neozed fuse links" data sheet 4121 and the German Wikipedia article "Schraubsicherung" (DIN VDE 0636-3), which agree from 2 to 63 A; D0 sizes also Altech’s catalogue. Class letters: the German Wikipedia article "NH-Sicherung" and VIOX’s IEC 60269 guide; gL as the older marking: Wikipedia and Littelfuse’s data sheet, which lists "gL-gG".
Before you send the fuse
Questions about fuse links in an RFQ
What is the difference between gG and aM?
The first letter is the range: g protects against overload and short circuit, a against short circuit only. The second letter is the use: G general purpose, M motor circuits. An aM link on a motor needs an overload relay beside it.
What does the coloured dot on a screw fuse mean?
The rated current: pink 2 A, brown 4 A, green 6 A, red 10 A, grey 16 A, blue 20 A, yellow 25 A, black 32 to 40 A, white 50 A, copper 63 A. The same colours mark the gauge rings that stop a larger link going in.
Which screw fuse size takes which current?
Diazed DII (E27) up to 25 A and DIII (E33) from 32 to 63 A; Neozed D01 (E14) up to 16 A, D02 (E18) from 20 to 63 A and D03 (M30 × 2) from 80 to 100 A.
What should the request include?
The type and size, the class letters, the rated current, the voltage (AC or DC) and the breaking capacity as printed, and the quantity. A photograph of the link and its holder shows what the marking leaves out.
Fuse read?
Send the line with the photograph.
A decoded marking is a cross-check, not proof. Attach photographs of the link and its holder, and Vessel Core checks them against each other before an offer goes back.
Buyer tools
