Question Is it safe to use fan socket splitter cables ?

[Pizztov]

Hello, Can I get some advise on the safety of using Fan splitter cables please. I have three available fan sockets with 3 front panel fans allocated. I have bought a M.2 Heat-sink that has a tiny fan. I'm looking to add a second M.2 with the same Heat-sink so have ordered a female to 3 male splitter. Is this a safe thing to do? I cant imagine the heat-sink fans will use much power.
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Crystal 6240 – RTX 4070Ti, Intel i7-12700F – Powered By ASUS PRIME B660-PLUS D4 Motherboard​

Corsair iCUE 4000X RGB Tempered Glass Mid-Tower ATX Case​

Thermalright HR10 2280 PRO Black SSD Cooler, Double Sided Heatsink, Carries 14.8W/m.k Silicone Pad, Includes 4 heatpipes, Reflow Process, 2280 SSD Heatsink Cooler For Desktop​

GeekerChip Fan Splitter PWM [2 Pack], PWM 4 Pin Fan Splitter 1 to 3,Fan Splitter Cable，Fan Splitter Cable PWM 1 to 3 Converter ​

 

[Aeacus]

MoBo fan headers are rated 1A at 12V. So, you have to add up all fan Amperage ratings and look if all combined are below 1A or not.
E.g 0.2A + 0.3A + 0.3A = 0.8A would be safe.
But 0.5A + 0.3A + 0.3A = 1.1A and it will fry the fan header. Most likely whole MoBo as well.

 

[Paperdoc]

Before panic sets in, recognize that MOST common case fans draw at most 0.10 to 0.25 A current, so THREE of those on one header IS OK. But to be sure, do as Aeacus says. FIND the max current spec of each fans (maybe from published specs, maybe from the fan label). IF the spec is in WATTS, Watts = Volts x Amps, and Volts is 12 VDC for this calculation.

Use a Splitter with 3 output arms to connect all three front intake fans to ONE CHA_FAN header and ensure it is set to use for its guidance the temperature sensor on the Motherboard. Before doing so, do the check on the current use max spec for those front fans.

Connect the fan on the M2 cooler unit to another CHA_FAN header, and configure it the same way. The slightly awkward item here is that ideally, you would use a temperature sensor ON the actual M2 unit(s) to guide this fan header. BUT there is no such sensor. So you can experiment. You could use for guidance here either the sensor on the Motherboard, OR the one inside the CPU chip. The mobo sensor is physically located near the M2 units. But the USE pattern of the M2 units is likely closely related to the general workload of the CPU chip. So that CPU temperature MAY be a closely related to the actual temperature inside the M2 units, and a good fan speed guide. To some extent you will be just guessing here. Unfortunately you have NO sensor to tell you the temps in the M2's, and you do not know whart that sshould be, anyway.

 

[Pizztov]

You guys are the best! Thank you so much for the help. Looks like I'll have to concentrate a bit and get my head round the math but, nonetheless, the advice you have shared is great. Thanks again. 👍🦖😀
ADDENDUM: Actually, the math is easy... DOH!!