Question Power Distribution: House to Server Rack
Question Power Distribution: House to Server Rack
I am trying to figure out what I am doing to wire up my server rack. Currently it is in my attic, but will eventually be moved to the basement. I cannot disclose why this is, I just need help with the power.
Input on my Server's PSU's (Dell R510) says 10A, theres 2, so I assume thats 20 right there. Thats the circuit to the room, in general. Redundant supplies though, so only one is active? How does that work?
All the networking input amperage adds up to 4.5A, and my PPC64 build stack adds up to 8-10A.
Each breaker is 20A, 2 hit the attic, and at the bottom of the stairs is a plug. I don't really expect everything to go to max? But I'm not sure.
How do I do the math here?
It's unclear what you're asking. You should measure the actual load of your equipment directly. Simple clamp meters on the hot lead work well, or you can use inexpensive power plugs that track usage. Of course, you'll need to account for occasional spikes in power demand, though it's unlikely you're connecting a window AC unit that causes big surges when it starts up.
After getting a reading, you’ll determine how many circuits you need to support the required amperage. If your equipment is brand new, you might run thick wire and set up one very high-amp circuit, similar to what’s used for stoves or dryers.
Most servers I’ve seen use redundant power supplies, running them simultaneously at about half capacity. This way, if one fails, the others take over. From my observations, these supplies rarely fail unless you unplug them or lose power unexpectedly. Many servers have three or more supplies, and it’s common to keep some in standby mode.
The ones with two supplies usually connect each cabinet to different circuits, ensuring that if one fails, others can keep the system running. The ones I often noticed had at least two dedicated large circuits feeding each cabinet, along with advanced power distribution and monitoring software. There are also cases with 20+ servers in those racks, not just two.
I recommend you:
1) Draw and share the existing or available electrical circuits considering the attic area.
2) Draw and share the existing or available electrical circuits for the basement location.
3) Plan how you believe to arrange the necessary power connections to the server racks and other devices inside them.
The diagrams don’t have to be elaborate—just clear enough to display "before" and "after" setups.
Make sure to list each device along with its power needs.
Due to certain considerations, how precise should my sketch be?
I’m currently working on a floorplan that covers most of the house. If I measured it with a laser, it would just show L and W measurements.
The basement layout is planned for later, maybe in a year or two, possibly as a separate panel. There are no current plans there. It’s about 4 feet away from the breaker box, compared to the attic where I expect to combine three breakers.
https://ibb.co/3mdBftqW
X's indicate important locations
Main power panel ----> Breaker (Amperage) ----> outlets or devices connected (servers, network gear, PPC64 stack, etc.). Indicate voltage levels and breaker ratings.
Explain the calculations using the formula P = I × V, where P is watts, I is amps, and V is volts.
Search online for clear examples to understand the setup.
Make sure the circuit can safely support the load; otherwise the breaker will trip.
Do you know if your system operates at 120 volts or 240 volts?
120, I'm US.
I'm a bit distracted while doing a very slim mod on a 1660ti, right?
The 1,1 and G5 are both 5A.
The server has a set of redundant supplies that are 10A each.
The network stack is 4.5A, but it will drop lower when I move the firewall to a VM on the server and connect the network via fiber from a fiber card.
I'm planning to do some calculations and I think I can work out my limits per zone. Now I just didn't really know what to check first.
The server in question?
https://i.dell.com/sites/csdocuments/Sha...cSheet.pdf
In general, I only grasp a limited understanding of what you have and your intentions. You talk about moving the server from the attic to the basement. Your diagram shows only outlets on the second and third floors, and it seems those outlets are connected through two 20 Amp circuits. Other devices could be connected or powered via these outlets. Also, there might be lighting fixtures in those circuits. I’m not sure.
Regarding the attic and basement circuits? It’s not just about the amperage. The wiring must be appropriately sized to handle the expected current.
P.S.:
It goes beyond simple calculations. Don’t oversimplify the power needs and the related circuit or breaker requirements. Without more information, the only advice I’m confident giving is to hire a qualified electrician to check your home’s electrical system and the loads you plan to use.
Safety first.
That project is a 750 watt 80 plus golds. The electrical setup actually exceeds the breaker capacity. My family built the house when I was two years old, and my dad handled a full industrial wiring job. I see comparisons online to another job an electrician did, and his specs seem pretty basic.
The basement is noted as temporary, likely lasting only about a year or so. There are LED lighting fixtures installed—each just 2 watts, which shouldn’t be a problem. I’m aware of this because I frequently change the lights when better options come along.
As far as I understand, if I connect the attic circuit, only me would be handling it. Downstairs, I’m not sure. I’ll do some calculations and get back with the findings after a quick consultation.
I was reminded to use the ring tracer again. I’ll have to locate it, which will be a challenge. It’s currently estimated at 15 amps, not 20 (though I thought 20 was for 30), and I can confirm that since we still have the wire. I’ll also need to identify which circuits belong to which ampacity. This will help determine if I’m working with 30 or 45 amps available.
On the second floor, the two wall plugs at the bottom are on separate circuits. The one farther from my office draws more power, but there’s nothing on the circuit at the bottom of the stairs to the bottom wall. On the opposite side of the door, there are connections that might change later. I can’t touch that one, you’re right.
Incorrect assumption. The 10A figure on the label for each Dell PSU doesn't indicate a requirement for 10A. If it did, each power supply would consume 1.2kW continuously from the AC mains (120V x 10A = 1200W). That seems excessive.
10A represents the standard current rating of the connector on some computer PSUs and the cord's capacity.
When purchasing tires for a vehicle, the rating must align with the vehicle's maximum speed capability, regardless of constant high speeds.
The power usage of the Dell 510 fluctuates, but it rarely exceeds a few hundred watts—equivalent to roughly 1A to 4A, not 10A.
The Dell R510 is available in various setups with single or dual PSUs.
As others have mentioned, it's important to measure the actual power usage of each device such as servers, network switches, monitors, etc. My HP servers include two (dual redundant) 460W PSUs, yet the combined average draw of the entire server with eight hard disks is only 100W.
Likewise, items labeled 5A and 4.5A won't consume close to those figures. Simply adding these values won't give an accurate picture. A meter is necessary.
Meters are affordable and straightforward. Inspect each piece of equipment individually to gauge its average power use. Peak draw may be higher.
It really clarifies things now.
I just checked my equipment and found that the only AC volt meter I own is designed for alternating current. That’s why I received it. I’ll have to look for a DC version.
These sketches give me a clearer idea.