Author Topic: Using AC terminal blocks on DC project.  (Read 965 times)

0 Members and 1 Guest are viewing this topic.

Offline rickey1990Topic starter

  • Regular Contributor
  • *
  • Posts: 74
  • Country: gb
    • Beambuilder - robotics blog
Using AC terminal blocks on DC project.
« on: July 01, 2022, 10:37:49 pm »
Hi I am currently in the design phase of a "Micro" solar junction board/ distribution box for 12v DC. The board will feature a 12v 20a non fused terminal for kettles and a 20a fused side (25A Fuse) with 4 10a pluggable 5.08mm connectors.

I have picked out some connectors PCB-8 / K14 , for the power in and kettle out. They say they are rated 40A but there's not really much info on them. Would anyone know the maximum amps at 12v or have used them before.

Also I had a look at some images of 60A solar charge controllers but to me they look alot like the 5.08mm 300v 10A terminal blocks. Obviously 12@10a is 120W , 300v@10a is 3000W. But I assume there's some sort of rule when using them for DC. Or is it as simple as saying  you can run 3000w at 12v through it.


Kind regards ,
Rick
« Last Edit: July 01, 2022, 11:05:47 pm by rickey1990 »
 

Online BrokenYugo

  • Super Contributor
  • ***
  • Posts: 1078
  • Country: us
Re: Using AC terminal blocks on DC project.
« Reply #1 on: July 02, 2022, 02:31:27 am »
Amps are amps for the most part. AC/DC ratings are for things like switch and relay contacts.
 

Offline WattsThat

  • Frequent Contributor
  • **
  • Posts: 764
  • Country: us
Re: Using AC terminal blocks on DC project.
« Reply #2 on: July 02, 2022, 02:55:25 am »
Quote
Or is it as simple as saying  you can run 3000w at 12v through it.

No. 10 amps is the limit, not 250 (3000/12). AC or DC does not matter for a non-switching device, amps are amps as the previous posted stated. Think current = heat.
 

Offline rickey1990Topic starter

  • Regular Contributor
  • *
  • Posts: 74
  • Country: gb
    • Beambuilder - robotics blog
Re: Using AC terminal blocks on DC project.
« Reply #3 on: July 03, 2022, 03:14:24 pm »
Okay thankyou for your both your responses 😊.
 

Offline exmadscientist

  • Frequent Contributor
  • **
  • Posts: 338
  • Country: us
  • Technically A Professional
Re: Using AC terminal blocks on DC project.
« Reply #4 on: July 04, 2022, 08:43:30 am »
Part of the reason you see terminal blocks marked as "AC" or "DC" is that the clearance (spacing) rules are different for AC compared to DC. So when they test and certify it, they need to tell you not just the test voltage but the type as well. If you are truly (extra) low voltage you can safely ignore all of this.
 

Offline Jeroen3

  • Super Contributor
  • ***
  • Posts: 4067
  • Country: nl
  • Embedded Engineer
    • jeroen3.nl
Re: Using AC terminal blocks on DC project.
« Reply #5 on: July 04, 2022, 09:40:24 am »
In you image, the left one is good for "a few amps", say max 5A. Or peak up to 10A at 25c ambient temp for a high-end brand.

The right one can take more current, say 10A over the full temperature range. But only if you can mount it properly. Note that there will be mounting stress on the pcb junctions, and you're dependent on the crimp quality for the generated heat in the junction as well.

You can get the same type of green plug in terminal blocks, but with flat inside connectors, that can take up to 30A for reputable brands.
For example Phoenix Combicon Power (PCV).

In these instances you need to pay attention to the derating factors. For ambient temperature and parallel conductors.
This matters when you're going near the "advertised" maximum rating.
If those details are unavailable, the part is probably not suitable until you've done your own qualification.

Remember ohms law: P = R * I2
« Last Edit: July 04, 2022, 09:44:05 am by Jeroen3 »
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf