How many PC's on 1 outlet?

[Krypt0n1te]

Would like to know how many PC's one could run from 1 single 230v socket?

Lets say

1. 230Watt
2. 300Watt
3. 500Watt PSU's

Thanks

All hypothetical.

 

[Archer]

One socket should be able to provide ±3kW. Sockets are usually rated up to 15A so, 220V*15A*0.9 = 3105W. Estimate of 0.9 power factor should be close enough. You can figure out how many PCs that is from there...

 

[JIMMYtheSKULL]

I have connected just over 10 std pc's with 250 to 300w psu's but it varies. I reckon 3 should be fine, if not get your sparky to check you db board, as it should easily handle you 3 machines.

 

[LancelotSA]

This question is interesting as you find many multiplug extensions with up to 15 plug points on them (2 and 3 prong ones). Now if one of those is behind the entertainment centre it could easily have a media player, TV, DVD player, video machine, home theatre system, heater, lamp, decoder etc etc etc plugged into it... are the rules different for these things? If the load gets too much what happens? Will the DB just trip or will it spontaneously combust?

 

[labratza]

+1

 

[BigAl-sa]

Just remember, if you trace the plug connections in a normal suburban house, they all go back to a single circuit breaker on the DB (I have 3x20A circuit breakers for plugs). This means you can run any single plug with connections drawing current up to the maximum of the circuit breaker (of course, you won't be able to run anything on the other outlets).

You could also burn down your house when the cheap plug socket catches alight from too much current, even though it has the SABS mark

 

[Voicy]

One socket should be able to provide ±3kW. Sockets are usually rated up to 15A so, 220V*15A*0.9 = 3105W. Estimate of 0.9 power factor should be close enough. You can figure out how many PCs that is from there...

Archer's math is correct, on a 0.9pF it's almost exactly 3kW.

Keep in mind your PSU's are rated on their maximum supply capability, a 500W PSU won't always be pulling 500W, so you can get away with a domestic use variant allowing you to go over the 100% threshold.

Lance, multiplug extensions are for use of low powered home appliance mostly. So having multiple socket outlets feeding off one 15A wall outlet is not an issue. High usage equipment i.e. in kitchens only operate for brief moments at a time.

If load exceeds 15A the circuit breaker in the DB board merely trips. Nothing spectacular. No Hollywood effects. It's merely there to protect the conductors feeding the circuit from frying when too much current is drawn. Things only start getting interesting on higher rated systems where you get a direct line fault and the circuit breaker's fault current is under rated (2.5kA el-cheapo samites) and the circuit breaker explodes before it can react.

 

[Jab]

If load exceeds 15A the circuit breaker in the DB board merely trips. Nothing spectacular. No Hollywood effects. It's merely there to protect the conductors feeding the circuit from frying when too much current is drawn. Things only start getting interesting on higher rated systems where you get a direct line fault and the circuit breaker's fault current is under rated (2.5kA el-cheapo samites) and the circuit breaker explodes before it can react.

The fault current rating (ie 2.5kA) indicate the short circuit current it's able to clear, it have no relation to the overload current (ie 20A) really. The fault current is directly related to the transformer feeding the house, and those used in residential areas are almost never able to provide more than a 2.5kA fault current. So a 2.5kA should almost always be sufficient in a house. And I agree those CBI samite breakers are crap.

 

[Barfish88]

I got 3 pcs a fan printer modem 3 x speakers running off 1 outlet

 

[Hein_JHB]

I got 2 x pc's plus Printer, router, Home made 4 channel 30W each amplifier and a CB Radio, Top TV decoder, scanner, 2 x external hd's, 23inch Full HD LCD screen feeding from 1 power outlet with no problems and I can use everything at the same time

 

[Palimino]

Just remember, if you trace the plug connections in a normal suburban house, they all go back to a single circuit breaker on the DB (I have 3x20A circuit breakers for plugs).

Not so. I have a normal suburban house and plugs don’t all go back to a single circuit breaker on the DB. They are clustered onto ‘spurs’ (several separate circuits). You can have as many 'spurs' as you want (with their associated circuit breakers).

For example: One ‘spur’ (circuit) has all the bedroom plugs on it. Another ‘spur’ has the kitchen plugs (a heavy power user). The final spur has the lounge/living area plugs on it.

 

[howardb]

Currently running 4 PC's (with LCD's), 1 laptop, laser printer, scanner, router and hub, speakers on 3 multiplugs from 1 wall plug - been running this for 4 years (24/7) without issues...

It's all dependant on what the draw is from the supply. As mentioned above, if you have 3 PC's with 500w PSU's, they won't be drawing 1500w continuously

 

[Voicy]

The fault current rating (ie 2.5kA) indicate the short circuit current it's able to clear, it have no relation to the overload current (ie 20A) really. The fault current is directly related to the transformer feeding the house, and those used in residential areas are almost never able to provide more than a 2.5kA fault current. So a 2.5kA should almost always be sufficient in a house. And I agree those CBI samite breakers are crap.

I know dude, cascading down from 20kA K35D's fed from 500kVA transformers to distribution level etc. is part of my job. I was merely mentioning to Lance that the only way you'll see sparks is if a circuit breaker is under a direct fault current scenario. (Direct line fault as I mentioned). We spec 5kA and above for our boards only. I've seen FAR too many 2.5kA smoke trails on DB's.

 

[stroebs]

Had a similar issue with power when I set a fundraising LAN event up at my school. Solved all issues by bringing in modified 3-pin plug multiplugs and an extra 3-phase db board (with 10x3-phase outputs on it) - Turned the building's electricity off and wired the db board right into the mains. Successfully held 250+ people on that db board, with no more than 7 pc's to a 15A socket on the multiplug.

 

[LancelotSA]

Lance, multiplug extensions are for use of low powered home appliance mostly. So having multiple socket outlets feeding off one 15A wall outlet is not an issue. High usage equipment i.e. in kitchens only operate for brief moments at a time.

If load exceeds 15A the circuit breaker in the DB board merely trips. Nothing spectacular. No Hollywood effects. It's merely there to protect the conductors feeding the circuit from frying when too much current is drawn. Things only start getting interesting on higher rated systems where you get a direct line fault and the circuit breaker's fault current is under rated (2.5kA el-cheapo samites) and the circuit breaker explodes before it can react.

In hindsight this is something I should be aware of as we have had the issue in our scullery. The washing machine was on as well as the dishwasher. The GF put on the kettle, which was in the same multiplug and the unit tripped (it was one of those with a built in "trip switch").

 

[Voicy]

Had a similar issue with power when I set a fundraising LAN event up at my school. Solved all issues by bringing in modified 3-pin plug multiplugs and an extra 3-phase db board (with 10x3-phase outputs on it) - Turned the building's electricity off and wired the db board right into the mains. Successfully held 250+ people on that db board, with no more than 7 pc's to a 15A socket on the multiplug.

Ooh, OC lan? I still remember back when I was still doing my BTech in Elec eng the german lad there with ties to WA (I sadly forgot his name, real awesome guys) asked me about it. He'd just managed to incorporate one into their lans. What I really liked was that they had ammeters on each phase so they could keep phase balancing in mind to see which phases were carrying the most/least load.

 

[stroebs]

Ooh, OC lan? I still remember back when I was still doing my BTech in Elec eng the german lad there with ties to WA (I sadly forgot his name, real awesome guys) asked me about it. He'd just managed to incorporate one into their lans. What I really liked was that they had ammeters on each phase so they could keep phase balancing in mind to see which phases were carrying the most/least load.

We had a similar setup with the balancing, so that the correct voltage was supplied to each outlet as well as balancing the power over all phases or it was manually adjusted to different ratios, depending on how many PCs we had on which side of the hall.