Daisy chaining power strips?

In reply to the lovely yellow text, my green text...

I've always been told this was an absolute no-no and thus have adhered all my life to the rule that this should never be done. Good. Keep it up.

However with the outlets in my current flat it's really bloody awkward to have extension leads all over the place... Oh-Oh

...and life would be considerably easier if I could daisy chain a few together. Ah, an easy life. When did that ever lead to trouble?

So, putting my logical head on, I cannot see the problem? Oh well, that's it decided then! :D

So long as the total load across two power strips does not exceed the total power limit of the first strip, it shouldn't cause an issue? Wrong. The maximum load of the first strip is based on the characteristics of the first strip... once you add another strip on to it you then have something different. You did say you had your logical head on, right? Surely the second strip is seen to the first strip as a single load though? My first strip is rated to 10A, therefore can take 2.3KW. Remove the 8.5w (lets call it 10 for easy maths), that leaves us with a theoretical maximum of 2.29KW to "spare". If the second strip has a load less than this figure, surely the strip does not know it is from a multiple sources on another strip, or perhaps say a kettle or a fan heater, which nobody would think twice about running in this situation?

Perhaps the resistance of the extra connections may cause some reduction in power limit but I imagine this is minimal on our voltage-high amperage-low power we have in the UK? You have quite the imagination. Voltage-High/Amperage-Low? That's not unique to the UK, it's part of the laws of the Universe. It's true that voltage is indirectly proportional to current, but I've no idea what the relevance is. Using words like "perhaps" and "imagine" should be enough of an indicator that you're having a stab in the dark here, mate. A little bit of stabbing, otherwise I would have not started this thread. The relevance of I vs V is important, as high currents cause heat when passed across a resistance, not high voltage. Going by Joule heating, being that P = I^2 R, then a halving of voltage (such as in America) would cause a doubling of current draw, and thus a 4X increase in heat produced if this current was passed along a wire with a fixed resistivity. We could expand this into the Peltier effect to measure the heat increase over the terminals within my plugs, however I am not knowledgeable of the Peltier coefficients of the components within my extension leads so we can count those as negligible.

If I were running several plugs at their limits, the way the power is delivered (as in P=IV) is incredibly important if heat is your main concern.

So before I go blow myself up, I am looking to install strip B, into strip A. Strip A will have one Phillips Hue bulb only and be plugged into the wall. Strip B will have my PC (750w PSU with only one GPU, I'd estimate ~400W max.), my monitor and some KEF Egg speakers. These will be plugged into strip A through a WiFi plug. So you've convinced yourself that "So long as the total load across two power strips does not exceed the total power limit of the first strip, it shouldn't cause an issue" ... and then you've decided to stick a WiFi plug right in the middle of it all. The purpose of a WiFi plug is to be the conduit for 3 extension leads carrying various items of electrical equipment? Really? Incorrect, the wifi plug only carries the computer, not the 8.5w (perhaps a little more due to the resistivity and resistance of my Ikea lamp's wiring) from the Philips Hue bulb. Given if I maxed out my 750w PSU, my monitor (according to Samsung) draws maximum 100w and my speakers running a 63w brick (if for some reason they drew the max current) then I would have a maximum of 913W. What is different between an extension lead with this combined power useage or say, a 900w Microwave?

Am I stupid? Probably not, but you do give an insight into the mental thought process that we go through as human beings, all to justify doing something that we knew was wrong right from the start. Correct, I wanted to run this setup as it's the only easy way for me to do it within the room my PC resides and as a human I am lazy and want my cake and to eat it. Or should that be I want my PC in the far right hand side of my room with the nice view and to power it? The whole point of a forum is to gain advice or discuss. In this case I was hoping for reasons why it is not a good idea to do it. Right now, you've said it's not, but have yet to provide real reasons why it's a bad idea?

Indecently, I do agree with you, a fuse is a last line of defence to protect you in the event of too much current being drawn. It is, however, largely irrelevant to my situation as I hope never to draw that sort of current. To be anal, the maths given worse case scenario would be a total draw at the wall of 921.5W, add 10% for losses (very generous) is 1013.65W, at 230v this is 4.407A, giving me a plentiful headroom over my 10A strip.
 
Indecently, I do agree with you, a fuse is a last line of defence to protect you in the event of too much current being drawn. It is, however, largely irrelevant to my situation as I hope never to draw that sort of current. To be anal, the maths given worse case scenario would be a total draw at the wall of 921.5W, add 10% for losses (very generous) is 1013.65W, at 230v this is 4.407A, giving me a plentiful headroom over my 10A strip.

You're right, that's why forums exist... to share knowledge. I'll respond properly later, I'm just too busy right now.

Hold on, aren't wall terminals daisy chained anyway?

No, they aren't. Your "daisy chain" is a radial circuit from the outlet. The outlet itself is in the form of a ring main, which is very different in terms of current carrying capacity.
 
It's not "very different". It can carry twice the amount of current as a spur.

It has higher current carrying capacity and it reduces volts drop. The point is, it's not "daisy chained" like extension leads are, which is the comment I was replying to. I'm happy to omit the word "very" if it makes you happy. ;)
 
It has higher current carrying capacity and it reduces volts drop. The point is, it's not "daisy chained" like extension leads are, which is the comment I was replying to. I'm happy to omit the word "very" if it makes you happy. ;)

The point being made is that if you have 2 power strips plugged in to a spurred double socket. The cabling in the wall is subjected to the same current as the power strip cable would be if you had them daisy chained.

Likewise, if you had 4 power strips plugged into 4 outlets on a ring main, the cable in the wall will be subjected to the same current as the power strip cables would be if you daisy chained 2 of them.

The bottom line is, it's not the daisy chaining itself that's the problem. If I daisy chained 6 power strips together and plugged 1 appliance into the last one, it's no more dangerous than just using one power strip. Likewise, if I plug 10 appliances into 2 daisy chained 5-way power strips, it's no more dangerous than if I plugged the same 10 appliances into a single 10-way power strip. The safety concern is simply using too many high powered appliances on a powerstrip that's under-rated for the task.

I have pretty much everything in my PC room running off 1 double socket via a UPS and daisy chained power strips. There is no safety issue at all as the total current draw is way less than the max of any of the strips.
 
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The point being made is that if you have 2 power strips plugged in to a spurred double socket. The cabling in the wall is subjected to the same current as the power strip cable would be if you had them daisy chained.

Likewise, if you had 4 power strips plugged into 4 outlets on a ring main, the cable in the wall will be subjected to the same current as the power strip cables would be if you daisy chained 2 of them.

What's your point? The cabling in the wall is irrelevant as it's rated for 32A if it's in a ring configuration, the daisy chained power strips aren't rated at 32A. :confused:

Anyway, people are quoting maximum power rating like it's relevant when it's not. As I said, I'm happy to elaborate on that but I don't have the time right now.
 
My point is I'm really not getting your argument against daisy chaining. As long as all the appliances are drawing less current than one of the power strips can handle, there isn't an issue.
 
My point is I'm really not getting your argument against daisy chaining. As long as all the appliances are drawing less current than one of the power strips can handle, there isn't an issue.

OK, I get you. I'll cover that when I post later (mad busy at work, so not avoiding just prioritising :) )
 
Just to clarify, my main question would be...

Say I have 16 appliances that together draw 8A. I can plug them all into a 16-way power strip (Rated at say 10A) safely, but if I plug them all into 4 daisy-chained 5-way strips of the same rating it's not safe. Why?
 
Just to clarify, my main question would be...

Say I have 16 appliances that together draw 8A. I can plug them all into a 16-way power strip (Rated at say 10A) safely, but if I plug them all into 4 daisy-chained 5-way strips of the same rating it's not safe. Why?
You could see one extension fail unsafely which then causes issues with the others. As stated above, you increase the likelihood of a 4-way extension failing safely by 16x, if plugged in to another 4-way. You’re dealing with 2 “devices” each carrying multiple appliances, instead of one device carrying them all.

Typically if your single extension goes pop, that’s it.
 
But electrically there is no difference. The 16 sockets in the 16-way strip are daisy chained in exactly the same way as they would be in 4 separate strips. The same argument could be used by saying that if one of the outlets on the 16-way were to fail unsafely then it would cause issues with the other 15.
 
There's some terrible advice in this thread. :mad:



If it goes above 13A it won't necessarily blow a fuse. Blowing a fuse is the last thing you want to do, it's not a testing device it's your last line of defence against fire or shock. The current being drawn from your 13A socket should never be anywhere near 5 amps let alone be in excess of 13 amps.



Before something goes on fire, it tends to heat up. That's what was happening in your example, and your power meter can only tell you how much power is being drawn... It can't tell you the resistance of the cable or whether it is capable of carrying the current you were putting through it.

Electrical cables should never, ever be hot. If cables are hot, it means they're pulling too much current and the fuse hasn't blown. That's a potential disaster in terms of safety.

Well, yes and no.

Getting hot is bad, and yes Fuses are poor protection against a steady state overload. During a portable generator test some years ago I successfully plugged two 3Kw heaters into a strip protected by a 13 amp fuse without it blowing. Though things did get a bit hot and smelly after an hour or so, so do not try this at home (No, really dont) :)

On the other hand, of course you can draw 13 amps from a 13 amp plug/wall socket. That is what it is for! (EG 3Kw fire)

Indeed, the Minimum BS standard for a twin wall socket is 20 amps total continuous, and yes it is also therefore physically possible to plug 2x3Kw into a single twin wall socket without blowing any fuses while at the same time dangerously overloading it, so you do have to be careful even if you are not using power strips. (Some manufacturers DO produce "over rated" sockets that can allow the full 26 amps. (MK possibly) But you need to check the back of the socket where the rating is normally stated, to be absolutely sure)

In principle, a 12 way strip (See http://www.network-cabling.co.uk/store/product_info.php/way-power-strip-vertical-p-93) is no different to three daisy chained 4 way ones.

In practice, Where you might very likely come unstuck is if you are using daisy chained power strips to supply electricity to heavy consumers. Just because the main plug/wall-socket has a 13 amp capacity does not mean that the sockets on the strip do, so if you are drawing a load of power from downstream strips you might overload the relevant socket on the first one and set fire to it.

OP has a similar situation to many people nowadays. A plethora of low wattage devices, none drawing more than 50 watts or so(Many drawing less than 10), but all requiring their own socket.

This is really a bloody nuisance.

If anybody is that bothered about the safety. Don't use a 13A fuse in the primary strip. Use a 5A one (Or even 3A), for extra safety, use a fast blow one rather than a slow blow.

TL;DR version.

Using a single 12 outlet power strip to run a LAN party with a dozen high end, overclocked PC's=Bad. You will probably burn the house down without blowing any fuses.

Using 3 daisy chained, 4 socket power strips to charge a load of mobile phones via USB power supplies = No Problemo. (Hell, you could safely daisy chain a dozen or more, 4 socket strips, in this scenario)

The problem here is about giving idiot proof advice, the devil is in the middle ground. As I said. Stick a low amp fuse in the main plug and you should really not have a problem, ever.
 
Don't use a 13A fuse in the primary strip. Use a 5A one (Or even 3A), for extra safety, use a fast blow one rather than a slow blow.
At the risk of stating the obvious, it's probably worth mentioning that you should only ever use a BS 1362 fuse in a plug. Some fast-blow types (e.g. the glass ones) might not be able to (quickly/safely) interrupt the fault current that a dead short somewhere could cause.
 
But electrically there is no difference. The 16 sockets in the 16-way strip are daisy chained in exactly the same way as they would be in 4 separate strips. The same argument could be used by saying that if one of the outlets on the 16-way were to fail unsafely then it would cause issues with the other 15.

@EVH has answered this, but you seem to be blinded by the numbers and the flawed appliance of science.

@Orionaut has also made some fine points.

I don't really see the point in regurgitating what they've said with different words. I would however, like to debunk a couple of myths.

1. You can load it all you like, the fuse will save you. This is a myth because, as previously stated, every electrical fire ever started did so where a fuse didn't blow. If the fuse had blown, there would have been no current to start the fire. Fuses don't protect against fire hazards, we rely on good practice and common sense to do that. In actual fact, a blown fuse or tripped circuit breaker could actually start a fire as it's an ignition source at the point of rupture. Fuses are there to protect the cable and equipment during short circuit conditions.

2. 13A sockets can be loaded up to 13A. These sockets are designed to withstand 13A, they aren't designed to provide 13A. Let's forget the amps and volts for a second and speak in terms that everyone understands: Money. If you loaded up one single 13A socket with every one of those 13A and run it 24/7, it would cost you roughly £33/month (£400/year) at an average price of £0.20/Kwh. That's just one single plug. The average house has around 20 of these socket outlets, each with 2 gangs that can "give you 13A". That's us now consuming around £1,333/month (£16k/year). No one consumes that amount of electricity in a domestic dwelling, which is why domestic installations aren't designed for that level of consumption.

Put in terms that the Geekdom can understand, a rig running 1080ti QUAD SLI would not consume 13A. You would have to plug in at least 3 rigs running QUAD SLI to come close to consuming 13A.

13 is a realtively small number, but 13A is not a small amount of electrical consumption in a domestic context.

I have pretty much everything in my PC room running off 1 double socket via a UPS and daisy chained power strips. There is no safety issue at all as the total current draw is way less than the max of any of the strips.

I've driven a car at 130MPH and I didn't have an accident. By your logic, it's perfectly safe to drive at that speed on a public road. Like I said, you're blinded by the numbers and you're biased because you switch the switch on and it works, therefore in your mind it's safe.
 
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Still not seeing any reason as to why daisy-chaining specifically is more dangerous than having the same appliances on a single strip.

@EVH has answered this, but you seem to be blinded by the numbers and the flawed appliance of science.

Why? Explain? The quote you made of mine was actually in response to EVH, not the other way around.

I've driven a car at 130MPH and I didn't have an accident. By your logic, it's perfectly safe to drive at that speed on a public road. Like I said, you're blinded by the numbers and you're biased because you switch the switch on and it works, therefore in your mind it's safe.

That's a ridiculous analogy tbh. I'm not at all blinded because "I switch the switch and it works". My UPS shows that all my daisy chained power-strips & appliances are using 500W. I feel confident that all the power-strips I'm using are capable of handling this. My point is, why is using 2 5-way power-strips any more dangerous than using 1 10-way?
 
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Read my edit.

Yep, read mine ;)

You seem to suggest that with my current setup I'm somehow "dicing with death". Please explain how exactly? And please explain how exactly by swapping my 2 daisy-chained power-strips for 1 larger one I'd be any safer?
 
That's a ridiculous analogy tbh. I'm not at all blinded because "I switch the switch and it works". My UPS shows that all my daisy chained power-strips & appliances are using 500W. I feel confident that all the power-strips I'm using are capable of handling this. My point is, why is using 2 5-way power-strips any more dangerous than using 1 10-way?

Because your 1 10 way is designed to provide 10 and your 1 5 way is designed to provide 5. When you start to join them together, then you are operating them outwith design.

Your 10 way strip has all the sockets linked by solid busbars inside the strip. All the interconnections are mechanically protected by the plastic moulding. More importantly, there is a CE label affixed to the socket to tell you that the 10 sockets, in this format, have been tested for mechanical and electrical integrity and that the unit has met the standard. When you start to daisy chain, you are creating connections that as @EVH has pointed out will increase your risk. It's not all about amps and volts. You now have a cable that is strewn from one strip to the other, and it doesn't have the same level of mechanical protection as a busbar encased in a plastic mould. If that cable is tucked under a carpet, then the current carrying capacity of that section of the circuit is now compromised and reduced due to the increased heat. If there is a fray at the stud of one of the plug pins, then the current carrying capacity of the cable has been compromised further. At no point during these fault conditions has the amount of watts you are consuming been increasd or decreased, the risk is from the mechanical damage. These set ups can be in use 24/7 month after month, sometimes for years... and that's where deterioration starts to play a part, because the increased heat is starting to erode the insulation resistance properties of the cable and a viscious circle is in full flow.

It's a culmination of factors and a compounding of risk. Your UPS is telling you the same thing the previous poster's power metre was telling him at his LAN party, and if he paid attention only to the number on that digital display then he could make the same claim as you. However, he put his hand on the cable and he can confirm that it was heating up, and that was only run for 48hrs not 48 months.

My analogy was accurate... just because your setup hasn't set your house on fire, it doesn't mean that your setup is safe. It's not about adding up numbers and calculating figures, it's about good practice and common sense.
 
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