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# How does the PCB board carry high current?

#### gavinray

##### Newbie level 5
The design current of the PCB board is usually a small current, so how to make the PCB board able to withstand a larger current? The electronic products used in daily life are only tens of milliamps to several amps. If there are tens of amps or more than 100A, it must not directly cause board burns or safety accidents. So what can be done to address such concerns?

This method is the most used method in our PCB design, because the wider the trace on the PCB, the greater the current carrying capacity. But trace width is not linearly related to current carrying capacity. Assuming that under the same conditions, a 10mil trace can withstand a current of 1A, but a 50mil trace cannot withstand a current of 5A.

Therefore, we need to understand the structure of the PCB at this time. Taking a simple two-layer board as an example, this circuit board is usually a three-layer structure: copper skin, plate, and copper skin. Among them, the copper skin is the main path through which the current and signals in the PCB pass. The common high-current PCB design operation methods in our design are as follows:

(1) Increase the line width, usually 1A 1mm (40mil);

(2) Copper thickness, 1oz, 2oz+++;

(3) Open the window on the wire, add tin, silver, copper, etc.;

In fact, in engineering, there is no strict standard for the length of wiring. Engineering is usually used: copper thickness / temperature rise / wire diameter, these three indicators to measure the current carrying capacity of the PCB board. We can also use the following two tables to understand how to increase the copper thickness and widen the wire diameter, so as to improve the heat dissipation of the PCB and enhance the current carrying capacity of the PCB

#### barry

##### Advanced Member level 6
Is that a question, or are you just trying to show us you that you know something? Like how to not post “the following two tables”, or how you think there is wire on PCBs? I don’t understand the point of his post.

And, by the way, there’s no way you’re going to have a PCB carry 100 amps.

#### marce

##### Advanced Member level 5
IPC-2152... The standard to work to. Saturn PCB Toolkit will do the calcs for you...

You can also vary the copper weight, Done boards and flexi's with 4, 6 and 7 ounce copper...