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Stopping Power Cuts causing DLM to Respond

Seasoned Hero
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Stopping Power Cuts causing DLM to Respond

In the night we had three power cuts about 15 minutes apart. This has resulting in my SNR increasing from 3 to 3.5dB and a small decrease in speed. As this was in the night I did not need the internet and that got me thinking.

In the days before I got rid of the old Fuse Box and got it replaced with a modern Consumer Unit with residual current protection I used plug in RCDs for portable appliances. I still have a few in my junk box. Most of these need a button to be pressed to make the connection which drops if there is a loss of power.

I could use one of these with my hub so that if I have a power drop I have to go and switch it back on again to get the hub back on. This would have turned last night’s event into a single drop which would not have caused any DLM action.

The downside would be that it might not ride out brown outs during the day, so it's a toss up. The other issue is that I have a security camera and NAS unit both connected to a switch that is connected to the hub. I am assuming that without the Hub running I will lose the connection between the camera and the NAS. So maybe I need to reinstall and power my separate modem only from the RCD and use my FTTP Smarthub in router mode, so that only the Modem remains off, options, options...

Yes,I know about UPSs but that is not justified on cost grounds.

Maybe I'll just put up with the slight speed drop for a week or two as it doesn't happen that often!

11 REPLIES 11
Community Veteran
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Re: Stopping Power Cuts causing DLM to Respond

Hmm.... If i am reading and understanding correctly... you had 3 power cuts during the night..... 

Q 1....   How do you know that ?

 The resultant power cuts changed the SNR value. 

Q2. ... How do you know that ?

To counteract this situation in the future.... you are saying that you want to "protect" your router/psu with an external RCD,. which. as you rightly say, needs you to press a button or flick a switch to "make good" the circuit, after any voltage drop/surge causes it to trip.

In the above situation, you are saying that this will appear as "One drop" on the power cuts... and the SNR will not be affected..

Hmm... but.... if the RCD trips, and you are asleep, ( as I assume you were during the power cuts mentioned)  ? ?   then there will be no power supplied to the router/PSU until you get up in the morning and realise that there has been some power failure due to the fact that your router/psu is not connecting your computer to the internet, until you physically press that button or flick the switch on the RCD  ?

Under the current ( no pun intended ) situation, ... the PSU will automatically restart the router, and the connection... on the return of the power supply to the "consumer unit" ... 

 

 

Seasoned Pro
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Re: Stopping Power Cuts causing DLM to Respond

We had power outages yesterday for a total of 12 hours and I feel with more electricity usage and old electricity infrastructure these will become more frequent. This is clearly an event that the internet connection system does to actually understand!

I do not know what consequential speed losses are, if any, but with poor quality telephone wiring perhaps we should be grareful that we get reasonable speeds at all.

Of greater concern, and a bit off topic, is our near total reliance on an electricity supply for routine activities. Lighting, cooking, heating as well as communication. it can be rather cold in January! And you can't go to the pub nowadays either.  I am currently looking into Plan B.....

Community Veteran
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Re: Stopping Power Cuts causing DLM to Respond


@TeeGee wrote:

I am currently looking into Plan B.....


 

Spoon Whittling, around the camp fire ?   

 

Heating... Lighting... and something to do.... all in one place...  ! !

Seasoned Hero
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Re: Stopping Power Cuts causing DLM to Respond


@shutter wrote:

Hmm.... If i am reading and understanding correctly... you had 3 power cuts during the night..... 

Q 1....   How do you know that ?


The Hub Event Log records the disconnections and the restarting. Also when the power comes back it switched our phone backlight on for a short period which tends to wake my light sleeping SWMBO


 The resultant power cuts changed the SNR value. 

Q2. ... How do you know that ?


The Event log is showing the increased SNR and reduced speed.


To counteract this situation in the future.... you are saying that you want to "protect" your router/psu with an external RCD,. which. as you rightly say, needs you to press a button or flick a switch to "make good" the circuit, after any voltage drop/surge causes it to trip.

In the above situation, you are saying that this will appear as "One drop" on the power cuts... and the SNR will not be affected..

Hmm... but.... if the RCD trips, and you are asleep, ( as I assume you were during the power cuts mentioned)  ? ?   then there will be no power supplied to the router/PSU until you get up in the morning and realise that there has been some power failure due to the fact that your router/psu is not connecting your computer to the internet, until you physically press that button or flick the switch on the RCD  ?

Under the current ( no pun intended ) situation, ... the PSU will automatically restart the router, and the connection... on the return of the power supply to the "consumer unit" ... 


No, My computer is off at night anyway, although the NAS is continually powered. On the first drop the RCD will open and disconnect the Hub from the mains until I reset it the next morning. The power to the NAS and Ethernet switch will come back on when the supply is re-established, but not the Hub as the RCD has dropped out. In this case the Hub and hence the BT DLM would have seen just one drop and the power off for several hours rather than three drops in about half an hour. Consequently this should be recognised by the DLM as a proper disconnection whilst the three successive drops followed by a reconnection can be equally interpreted as being the line struggling and dropping the connection, triggering DLM intervention.

 

 

 

 

 

 

Superuser
Superuser
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Re: Stopping Power Cuts causing DLM to Respond

This has resulting in my SNR increasing from 3 to 3.5dB and a small decrease in speed.

@Baldrick1 that's almost certainly not a DLM change. It's more likely due to the time at which the router resynched. The background noise is generally higher during the night, so the sync speed was reduced slightly when it resynched, to maintain the 3db target. Later, when you checked it , the background noise was less and so the noise margin increased slightly. If you resynch again when the noise is less ( during the day ) , you'll likely get your speed back and be back at the 3db margin.

Seasoned Hero
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Re: Stopping Power Cuts causing DLM to Respond

@MisterW 

Thanks for the input. I will try a resynch tomorrow. I assumed it was DLM as it’s the lowest speed I have seen and a bit below myRange A VDSL speed.

Aspiring Champion
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Re: Stopping Power Cuts causing DLM to Respond


@TeeGee wrote:>and I feel with more electricity usage and old electricity infrastructure these will become more frequent. This is clearly an event that the internet connection system does to actually understand!

I do not know what consequential speed losses are, if any, but with poor quality telephone wiring perhaps we should be grareful that we get reasonable speeds at all.

Of greater concern, and a bit off topic, is our near total reliance on an electricity supply for routine activities. Lighting, cooking, heating as well as communication. it can be rather cold in January! And you can't go to the pub nowadays either.

I think you might be in for a shock (no pun intended :-)) regarding ageing infrastructure. Certainly round these parts we use to get power cuts on quite a frequent basis - definitely rural. Apart from one a few weeks ago, that was the first for quite some time. They have been putting up new cables, poles, transformers everywhere. Even cutting back the trees where they are too close. I know when I worked for the electricity supply, underground cables were expected to have a very long life i.e. 100 yrs or so. But who knows what will happen to the supply grid when electric cars become the norm.

 

But regarding @Baldrick1 problem. There are 2 types of RCD sockets i.e. passive or active. If you get an active socket you have to switch them back on after a power cut. Passive ones automatically reset themselves after a power cut.

 

Admittedly a UPS might be overkill for some but I do have one on the routers. We use to have lots of little power cuts and DLM would kick in. Now If I'm using the smartphone or the laptop, the internet connection continues as if nothing has happened. To me its a win win situation. I get to keep my speed. I seem to remember paying around £50 about 5 years ago and it has been well worth it. Don't need a massive one either.

Ever helpful. Grin Sure, I’d love to help you out. Now which way did you come in?
Seasoned Hero
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Re: Stopping Power Cuts causing DLM to Respond

@idonno 

As  @MisterW  predicted, my speed drop has been resolved by dropping the DSL, leaving it a couple of minutes then reconnecting. 
I’m not sure that I agree with your description of the two types of RCD. Passive ones do not automatically reset, they simply do not trip on loss of power.

Apart from the, I agree modest, cost of a UPS I am becoming more aware of the running cost of devices that are on 24/7. If you take the average electricity tariff, every watt used by a device continuously powered costs about £1.20 per year. With the number of devices in many homes this is becoming  a significant part of the electricity bill.

To be honest I suspect that paying for cloud storage would cost no more than running my NAS.

Aspiring Champion
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Re: Stopping Power Cuts causing DLM to Respond


@Baldrick1 wrote: I’m not sure that I agree with your description of the two types of RCD. Passive ones do not automatically reset, they simply do not trip on loss of power.

>every watt used by a device continuously powered costs about £1.20 per year. With the number of devices in many homes this is becoming  a significant part of the electricity bill.


True, you could call it stay set but the effect is the same. i.e. you don't have to reset it.

 

I don't know, even 10 items at 1.20 a year would be a pretty small price to pay for convenience. Even more so when my electric bill equates to £70 a month. It has got worse as the computers have been upgraded. The average (recent) graphic card uses around 200watts, some even more than that. While playing games I've sometimes thought about getting the fry pan out. Heat certainly does come out of the radiator under load. Even using 600w (3 hrs use) makes 1 watt per year costs pale into insignificance. And while it might help heat the house, oil is currently much cheaper then my electricity costs.

Ever helpful. Grin Sure, I’d love to help you out. Now which way did you come in?
Seasoned Hero
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Re: Stopping Power Cuts causing DLM to Respond


@idonno wrote:

I don't know, even 10 items at 1.20 a year would be a pretty small price to pay for convenience. 


If only each device only consumed 1 watt!
The majority will be several watts, others even more.
I went around and counted up the devices we have. These ranged from the router, NAS through to time switches, clocks, security systems wireless thermostats, etc, etc. I reckon  that I’m not far off a standing load of 100W, that’s over £100 per year.

 

 

 

 

Hero
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Re: Stopping Power Cuts causing DLM to Respond

Aye, these things mount up. My pond pump and UV filter is costing around £54 per year to run.

It's nearly a unit a day out of a total of an average of 6 per day.

The older I get, the earlier it gets late.

ADSL2+   Billion 8800NL