Numbering of contactors and relays in wiring diagrams 1

[RockClaudiu]

Hi,
I have some questions regarding how contactors and relays are numbered (tagged, identified) in wiring diagrams. I’m new with wiring diagrams and I see most of the times contactors are numbered K1, K2 or K3 and relays are numbered from K9, K10, K11 and so on.
Is there a rule how these components should be numbered? Is there a sequence for contactors, let’s say from K1 to K8, and relays follow from K9 onwards?
Thank you!

 

[oldfieldguy]

I prefer to segregate things a bit.

Relays perform control functions. Relays are K1, 2, 3.

Contactors switch power to end devices such as motors or lighting. Contactors get C1,2,3.



old field guy

 

[xnuke]

As far as I know, there is no rule.

xnuke
"Live and act within the limit of your knowledge and keep expanding it to the limit of your life." Ayn Rand, Atlas Shrugged.
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[jraef]

If you are using the numbering system using "K" numbering, that is based on an IEC / DIN engineering standard that does indeed dictate exactly what the numbers mean and how devices are numbered. If you are in North America, we don't use that numbering system at all, so what it means there is technically irrelevant. Still, even if you are in NA it would be prudent to use the IEC conventions if there is a chance that your equipment is being exported, or if your company hires people who may have been trained outside of NA, because for them, the numbering DOES mean something and ignoring the conventions creates a risk of misunderstanding. So either follow the convention or convert to JIC / ANSI symbols and numbering. Or ignore it all and accept the risks.


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

 

[ScottyUK]

The IEC 60947 series of standards define the terminal number for contacts, e.g. 11/12, 33/34, 95/96 and so on. These numbers have defined purposes, for example NO, NC, alarm, etc. I'm less certain that the K1, K2, etc have purposes defined by IEC. They may well be defined in something like the excellent KKS system.

 

[RockClaudiu]

Hi,
Thank you all for your input... I'm from Europe so the IEC standards apply and we are using "K" numbering for contactors and relays. Jraef, do you know which IEC standard is for the numbering of these components?

 

[jraef]

I think ScottyUK is right, 60947 is for terminal numbers. But the use of K or C or Q designators is related to IEEE 315, which I'm sure is based on an IEC spec somewhere but I don't know where.


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

 

[RockClaudiu]

Hi guys,
Coming back to subject... I did some research for the last few days but unfortunately I couldn't find anything concrete. I checked IEC 60947, IEC 61082, IEC 61346 but without success. The only thing I could find are some remarks in the EATON Wiring Manual, beginning of chapter 10 where is stated :

Marking to DIN EN 81346-2 (IEC 81346-2)
.......
Eaton uses the above standard.
In addition to that, Eaton specific decisions have been made with regard to the interpretation of the standard that sometimes deviate from the standard.

• The marking of connection terminals are not readable from the right.
• A second code letter for the marking of the use of the equipment is not given, e.g.: timing relay K1T becomes K1.
• Circuit-breakers with the main function of protection are still marked with Q. They are numbered from 1 to 10 from the top left.
• Contactors are newly marked with Q and numbered from 11 to nn. e.g.: K91M becomes Q21.
• Contactor relays remain K and are numbered from 1 to n.

Also I found in IEC 61346 (Table 1) that objects are grouped in classes according to their purpose or task and each group has a letter code associated... for example:

Code - F
Purpose or task of object - Direct protection (self-acting) of a flow of energy, signals, personnel or equipment from dangerous or unwanted conditions
Examples of typical electrical products - Fuse, Miniature circuit-breaker, Thermal overload release

Code - K
Purpose or task of object - Processing (receiving, treating and providing) signals or information (excluding objects for protective purposes, see class F)
Examples of typical electrical products - All-or-nothing relay, Contactor relay, Delay element, Synchronizing device, Time relay, Transistor

Code - Q
Purpose or task of object - Controlled switching or varying a flow of energy, of signals or of material. (For signals in control circuits, see classes K and S)
Examples of typical electrical products – Circuit-breaker, Contactor (for power), Disconnector, Fuse switch, Fuse-switch-disconnector, Motor starter, Power transistor, Slip-ring short-circuiter, Switch (for power), Thyristor... (If main purpose is protection, see class F)

Code - S
Purpose or task of object - Converting a manual operation into a signal for further processing
Examples of typical electrical products – Control switch, Discrepancy switch, Keyboard, Push-button switch, Selector switch

 

[jraef]

That is pretty much what IEEE315 says as well, so that's likely where it came from.


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington