Does power supply have to have metal case?

LearningToRepair · 11-22-2020, 11:44 AM

Hi!

I was thinking of making custom case for power supply. It currently has one small 6 cm fan which needs high rpm in order to keep it cool. However this makes it noisy. I had a thought that I would 3D print a larger case that have 2x 12cm fans that I would run with low RPM to keep them quiet. I figured that it is easier to 3D print a new case than do it from metal because I dont have tools to make precise cuts, bend it to right angle weld screw mounts and so on.

Would something be wrong if I 3D print plastic case instead? For example is it required to shield from radio waves or something or will it work just as fine in plastic case?

Some screws that connect PCB to case are connected to fault ground. I guess these I just have to wire connect to ground?

Has anyone ever attempted to build a custom case? Any success?

**sam_sam_sam** · 11-22-2020, 01:43 PM

Is this a computer switching power supply mostly in metal cases ( I do not have an answer for you about this type of switching power supply I do not want to give you the wrong information )

Or is just a switching power supply because this type of switching power supply are mostly made with plastic enclosure

**stj** · 11-22-2020, 03:31 PM

switching power supplies are in metal boxes for screening,
not to protect them, but because they are the source of rf noise.

if you dont use radio or give a shit then it will be fine in plastic - they used to sell coloured acrylic shells to customise pc psu's.

**petehall347** · 11-22-2020, 06:04 PM

aluminium tape works apparently

LearningToRepair · 11-23-2020, 11:58 AM

Quote:

Originally Posted by sam_sam_sam

Is this a computer switching power supply mostly in metal cases ( I do not have an answer for you about this type of switching power supply I do not want to give you the wrong information )

Or is just a switching power supply because this type of switching power supply are mostly made with plastic enclosure

It's general purpose SMPS from china. You know one that is used for LED lights, 3D printers etc.

Quote:

if you dont use radio or give a shit then it will be fine in plastic - they used to sell coloured acrylic shells to customise pc psu's.

How well do those frequencies go through wall? Would it kill neighbours radio/wifi behind concrete wall?

What's the exact frequency? The same frequency as switching?

Aluminium tape sounds good idea.

I dont even have radio at home so I have no idea how to verify if I have enough layers of aluminium foil. And if I put 2 large fans on top then the top of it would leak anyways.

**stj** · 11-23-2020, 01:54 PM

switching frequency - something usually between 30KHz and 1MHz + harmonics.
range will be short - 10's of feet, but if you have a radio operator next-door they will be effected because they use long-range ultra-sensitive antenna's

LearningToRepair · 11-24-2020, 02:33 PM

Thanks.

For humans it wouldn't do anything? I guess it wouldn't be much stronger than wifi/mobile networks that are already around us?

**goontron** · 11-24-2020, 03:09 PM

What you hear about RF being injurious to humans is all nonsense by those who don't understand how it works anyway.

It won't do anything to humans unless it gives off an audible whine. Then it'll give you a headache at worst.

**eccerr0r** · 11-26-2020, 01:11 PM

However, concentrated 1KW RF pointed directly at a person could do something...

Same could be said about connecting 120VAC and passing 8 amperes...

Fear of the unknown. RF, wireless communication, and microwave ovens are voodoo for most people out there and thus is "scary..."

**goontron** · 11-26-2020, 04:03 PM

MMmmhmm. So ive noticed.

People don't know math. Else they would understand magnitudes.

Thanks broken school system!

11-22-2020, 11:44 AM	#1
LearningToRepair Member Join Date: Jul 2020 City & State: * My Country: * I'm a: Knowledge Seeker Posts: 20	Does power supply have to have metal case? Hi! I was thinking of making custom case for power supply. It currently has one small 6 cm fan which needs high rpm in order to keep it cool. However this makes it noisy. I had a thought that I would 3D print a larger case that have 2x 12cm fans that I would run with low RPM to keep them quiet. I figured that it is easier to 3D print a new case than do it from metal because I dont have tools to make precise cuts, bend it to right angle weld screw mounts and so on. Would something be wrong if I 3D print plastic case instead? For example is it required to shield from radio waves or something or will it work just as fine in plastic case? Some screws that connect PCB to case are connected to fault ground. I guess these I just have to wire connect to ground? Has anyone ever attempted to build a custom case? Any success?

11-22-2020, 01:43 PM	#2
sam_sam_sam Badcaps Veteran Join Date: Jul 2011 City & State: Sunny Jacksonville FL My Country: USA Line Voltage: 120 Volts 60 HZ I'm a: Knowledge Seeker Posts: 2,336	Re: Does power supply have to have metal case? Is this a computer switching power supply mostly in metal cases ( I do not have an answer for you about this type of switching power supply I do not want to give you the wrong information ) Or is just a switching power supply because this type of switching power supply are mostly made with plastic enclosure __________________ 9 PC LCD Monitor 6 LCD Flat Screen TV 30 Desk Top Switching Power Supply 10 Battery Charger Switching Power Supply for Power Tool 6 18v Lithium Battery Power Boards for Tool Battery Packs 1 XBox 360 Switching Power Supply and M Board 25 Servo Drives 220/460 3 Phase 6 De-soldering Station Switching Power Supply 1 Power Supply 1 Dell Mother Board 15 Computer Power Supply 1 HP Printer Supply & Control Board * lighting finished it * These two repairs where found with a ESR meter...> Temp at 50F then at 90F the ESR reading more than 10% 1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later ) 2 Hem Saw Computer Stack Board All of these had CAPs POOF All of the mosfet that are taken out by bad caps

11-22-2020, 03:31 PM	#3
stj Great Sage 齊天大聖 Join Date: Dec 2009 City & State: Europe My Country: some shithole run by Israeli agents I'm a: Professional Tech Posts: 23,701	Re: Does power supply have to have metal case? switching power supplies are in metal boxes for screening, not to protect them, but because they are the source of rf noise. if you dont use radio or give a shit then it will be fine in plastic - they used to sell coloured acrylic shells to customise pc psu's.

11-22-2020, 06:04 PM	#4
petehall347 Badcaps Veteran Join Date: Jan 2015 City & State: worcester My Country: United Kingdom I'm a: Knowledge Seeker Posts: 2,520	Re: Does power supply have to have metal case? aluminium tape works apparently

11-23-2020, 01:54 PM	#6
stj Great Sage 齊天大聖 Join Date: Dec 2009 City & State: Europe My Country: some shithole run by Israeli agents I'm a: Professional Tech Posts: 23,701	Re: Does power supply have to have metal case? switching frequency - something usually between 30KHz and 1MHz + harmonics. range will be short - 10's of feet, but if you have a radio operator next-door they will be effected because they use long-range ultra-sensitive antenna's

11-24-2020, 02:33 PM	#7
LearningToRepair Member Join Date: Jul 2020 City & State: * My Country: * I'm a: Knowledge Seeker Posts: 20	Re: Does power supply have to have metal case? Thanks. For humans it wouldn't do anything? I guess it wouldn't be much stronger than wifi/mobile networks that are already around us?

11-24-2020, 03:09 PM	#8
goontron 5000! Join Date: Dec 2011 City & State: South Greeley, Wyoming My Country: US Line Voltage: 13.9kv HT service and some 240v center tap oddity. I'm a: Professional Tech Posts: 4,029	Re: Does power supply have to have metal case? What you hear about RF being injurious to humans is all nonsense by those who don't understand how it works anyway. It won't do anything to humans unless it gives off an audible whine. Then it'll give you a headache at worst. __________________ Things I've fixed: anything from semis to crappy Chinese $2 radios, and now an IoT Dildo.... "Dude, this is Wyoming, i hopped on and sent 'er. No fucking around." -- Me Excuse me while i do something dangerous You must have a sad, sad boring life if you hate on people harmlessly enjoying life with an animal costume. Sometimes you need to break shit to fix it.... Thats why my lawnmower doesn't have a deadman switch or engine brake anymore Tomorrow Is Nearly Yesterday And Everyday Is Stupid!

11-26-2020, 01:11 PM	#9
eccerr0r Solder Sloth Join Date: Nov 2012 City & State: CO My Country: USA Line Voltage: 120VAC 60Hz I'm a: Hobbyist Tech Posts: 5,272	Re: Does power supply have to have metal case? However, concentrated 1KW RF pointed directly at a person could do something... Same could be said about connecting 120VAC and passing 8 amperes... Fear of the unknown. RF, wireless communication, and microwave ovens are voodoo for most people out there and thus is "scary..."

11-26-2020, 04:03 PM	#10
goontron 5000! Join Date: Dec 2011 City & State: South Greeley, Wyoming My Country: US Line Voltage: 13.9kv HT service and some 240v center tap oddity. I'm a: Professional Tech Posts: 4,029	Re: Does power supply have to have metal case? MMmmhmm. So ive noticed. People don't know math. Else they would understand magnitudes. Thanks broken school system!

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