Is the PSU voltage mismatch actually that severe?
Is the PSU voltage mismatch actually that severe?
Hello everyone,
I wanted to check if it's safe to connect my PSU to a socket rated for 16 Amps at 380 Volts.
My circuit breaker sometimes trips when I try to switch the PSU to I or 1.
The PSU I have is the FSP Group Hyper 80+ Pro 700W, model H3-700.
I'm in a rural area and unsure about the local electricity quality.
I've attached photos of my PSU and home circuit breaker (Germany):
https://imgur.com/a/zZ2DFCI
https://imgur.com/GjtgGZO
https://pcpartpicker.com/list/rwZYxg
(Note: PSU isn't listed on PC Part Picker)
It all hinges on what else is connected to the same breaker.
The overall draw is 16 amps. This power source usually operates around 3 amps when fully loaded, but it's unlikely to reach even close to that during regular use.
When you first switch it on, it probably draws the full load for a brief moment—less than a second—while charging capacitors. Breakers are built to handle small spikes; however, appliances like refrigerators experience much larger surges when the compressor starts.
The exact amount depends on the combined amperage of all other devices sharing the circuit. If another device is already drawing 14 amps and you connect your computer, it could easily exceed the 16 amp limit and trip the breaker.
You’ll need to check what else is on the same circuit.
16 amps is a significant load—likely something like a heater or microwave is drawing too much power.
Another possibility is that the breaker itself is faulty. These components can degrade over time, often tripping only a few times before failing.
They are relatively easy to replace if you’re familiar with the process, but incorrect installation could be dangerous.
I calculated the amp settings using the power supply and 240 volts. The main principles remain unchanged. I’m now puzzled about the practical application. Germany’s outlets are 240 volts like the rest of the EU, so are the breakers rated for 380 volts? Or is the voltage actually 240 while another panel reduces it? Also, one breaker seems to be marked as faulty.
Circuit breakers in the EU work at approximately 230V yet are rated for 380/400V. For example, the models I own are B16 230/400 and B25 230/400, which means they either carry 16A or 25A, operate at 230V with a maximum of 400V. Follow what bill001g mentioned. When the PSU is active, you'll face an overload in the circuit. Either reduce the load on that circuit (turn off or unplug other devices), or swap the old breaker for a larger one, like the B25 model. Remember, only a qualified electrician should handle this. You might also contact someone at the site to pinpoint the exact problem.
Also, your FSP PSU isn't very reliable either. From the limited information available, it appears to be a low-quality power supply unit.
I question whether you're causing the breaker to overload by connecting too many devices. More likely, your MCB is tripping during the initial power-up surge on the ATX PSU, which can reach over 100A on certain models. In the test described, a 550W PSU draws 93.99A at 230V for a brief moment when switching on. This level is sufficient to trigger some sensitive MCBs. The fix would be to install a new MCB with a different tripping behavior, or choose a PSU that has a lower switch-on surge. You've ended up with a mismatched setup of PSU and breaker. It's best to consult an electrician. A standard Class-B MCB won't trip until you're drawing between 3x and 5x the rated current. For a 16A breaker, that translates to 48A to 80A. Going above the 16A rating by a few Amps is unlikely to cause tripping, but reaching 93.99A could trigger it. https://www.slideserve.com/king/mcb-trip...cteristics MCBs function using both thermal and magnetic mechanisms.
What you linked contains very old information. The presentation was made in 2002, which is 23 years ago. Today's circuit breakers have different settings—Class B trips at double the amperage and Class C at triple it. For example, a B16 trips at 32A, B25 at 50A, and C40 at 120A. This advice came from the certified electrician who visits our site twice yearly to check all electrical systems, ensuring compliance with codes.
Accepted. I corrected the reference to outdated information. I will review the applicable standards in BS 7671 18th Edition and compare them with local regulations. There might be differences from EU and USA rules in certain areas. Previously, I thought all homes had a safety earth on their main sockets except for specific devices like shaver sockets, but I now understand this isn't always the case elsewhere.
Please note that my home still uses old ceramic fuse holders without MCBs, only having 5A, 15A, and 30A fuses plus a card to rewire blown fuses. Also, I don’t have any asbestos in the fuse holders.
I still think it’s unlikely a 16A Class B MCB will trip due to a few extra continuous amps from an ATX PSU, unless the circuit is already near overload with close to 30A. Instead, I believe it’s more likely the short duration surge from the ATX PSU (usually 30 to 100A) that causes the breaker to trip.
When reviewing Tom’s comments about ATX PSUs, I prefer models with a surge switch under 50A at 230V AC and avoid those with surges over 70A. The example he mentioned was quite high—around 94A—and could easily trigger sensitive MCBs.
I’m fortunate to have all my appliances on several 30A ring mains rather than 16A circuits, giving me nearly double the capacity compared to the OP. So far, I haven’t blown a 30A ring main fuse in any of my ATX PSUs.