Hi, I upgraded to a new heated bed with a silicone heater with 300 Watts at 12V. Before I had about 200 Watts at 15V. The cables have a cable cross section of 2,5 mm². Doing the math the new one will draw 25 Amps (old one 13,3 A). The bed is well insulated and at 50°C its not on very often, so the cables don't heat up. When the bed is set to 100°C the cables get a little bit wormer after a few minutes (about 30°C, room temp 24°C). So my question is, is it still save to use 2,5mm² cables? https://reprap.org/forum/read.php?406,771224,771224#msg-771224 Mon, 20 Jul 2026 08:59:06 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?406,771224,771523#msg-771523 https://reprap.org/forum/read.php?406,771224,771523#msg-771523 Solder the new wire to the heatbed wire in a save distance. Remember the heat from the bed heater is creeping up the cable, too.]]> o_lampe Prusa i3 and variants Sat, 03 Jun 2017 02:16:49 -0400 https://reprap.org/forum/read.php?406,771224,771467#msg-771467 https://reprap.org/forum/read.php?406,771224,771467#msg-771467
Which cables should I get and what is the difference?]]> h4nc Prusa i3 and variants Fri, 02 Jun 2017 13:55:29 -0400 https://reprap.org/forum/read.php?406,771224,771466#msg-771466 https://reprap.org/forum/read.php?406,771224,771466#msg-771466
2.5 (14AWG) is the bare minimum for a 2% voltage drop at ~25A. I may have been a little enthusiastic with my 5.26 (10AWG) estimate, but I like to add in a 20-50% buffer. Since you're replacing the speaker wire anyway, I suggest getting 3.31 (12AWG).

Some areas you don't want to skimp on wire size: constant-on, high-temp, and high current, such as bright lights, heating elements, and drive motors.]]> irab88 Prusa i3 and variants Fri, 02 Jun 2017 13:50:25 -0400 https://reprap.org/forum/read.php?406,771224,771374#msg-771374 https://reprap.org/forum/read.php?406,771224,771374#msg-771374
I attached a sketch of my setup. The silicone heatbed cable is 2,5mm², length about 40cm.

The cable from the XT60 connector to the power supply is a 2,5mm² speaker cable. The length is approximately 120cm.

So the total length is about 1,6m.

Wouldn't it be useless to use bigger cables at one section, while leaving it at 2,5mm² at the silicone heated bed?

Also the manufactor chose an 2,5mm² cable for the heated silcone pad. Shouldn't this tell me that is is save to go with the 2,5mm²?]]> h4nc Prusa i3 and variants Fri, 02 Jun 2017 04:35:55 -0400 https://reprap.org/forum/read.php?406,771224,771361#msg-771361 https://reprap.org/forum/read.php?406,771224,771361#msg-771361 I'd leave it as is. A 2.5mm² cable is good for up to 50A peak.]]> o_lampe Prusa i3 and variants Fri, 02 Jun 2017 02:42:15 -0400 https://reprap.org/forum/read.php?406,771224,771258#msg-771258 https://reprap.org/forum/read.php?406,771224,771258#msg-771258 irab88 Prusa i3 and variants Thu, 01 Jun 2017 09:49:22 -0400 https://reprap.org/forum/read.php?406,771224,771224#msg-771224 https://reprap.org/forum/read.php?406,771224,771224#msg-771224
I upgraded to a new heated bed with a silicone heater with 300 Watts at 12V. Before I had about 200 Watts at 15V.

The cables have a cable cross section of 2,5 mm². Doing the math the new one will draw 25 Amps (old one 13,3 A).

The bed is well insulated and at 50°C its not on very often, so the cables don't heat up.

When the bed is set to 100°C the cables get a little bit wormer after a few minutes (about 30°C, room temp 24°C).

So my question is, is it still save to use 2,5mm² cables?]]> h4nc Prusa i3 and variants Thu, 01 Jun 2017 04:58:45 -0400