Electrical power adaptor ratings?

HappySeagull

So, my friend woke up this morning... no phone line, no broadband, etc. Called BT and they're sending an engineer... next Wednesday.

It's obviously a power problem, as there are no lights on the modem thingy (fibre-to-the-premises boxes). Having been out all day, the though occurred to simply plug in another power adaptor - bingo, flashing lights. :T

Just not sure about the power ratings - the original plug says 12v, 1.0amp, and the replacement says 12v, 1.5amp. Both have a black nozzle at the end.

Is is safe to continue using? Will BT get upset at my friend?

googler

If the original is rated at 1.0A, that suggests that the modem won't draw any more power than that from the adaptor - in which case, your 1.5A adaptor is easily capable of supplying that.

Where you'd have problems is the situation I'm in - I want to connect a car tyre compressor, which normally runs off the cigarette lighter or accessory socket in the car, to a mains adaptor, but the compressor is rated at 7.0A, whereas the most powerful adaptor I have handy is rated at 3.0A. In this case the compressor will try to draw more power than the adaptor can supply, and would probably overheat the adaptor.

Strider590

Power supplies which are used 24/7 should be chosen carefully, use branded power supplies, avoid cheap Chinese rubbish which are often poorly designed/constructed and could cause a fire.

HappySeagull

Strider590 wrote: »

Power supplies which are used 24/7 should be chosen carefully, use branded power supplies, avoid cheap Chinese rubbish which are often poorly designed/constructed and could cause a fire.

This is a power supply from an external hard drive, so I would hope/expect it would be decent quality.

HappySeagull

googler wrote: »

If the original is rated at 1.0A, that suggests that the modem won't draw any more power than that from the adaptor - in which case, your 1.5A adaptor is easily capable of supplying that.

Where you'd have problems is the situation I'm in - I want to connect a car tyre compressor, which normally runs off the cigarette lighter or accessory socket in the car, to a mains adaptor, but the compressor is rated at 7.0A, whereas the most powerful adaptor I have handy is rated at 3.0A. In this case the compressor will try to draw more power than the adaptor can supply, and would probably overheat the adaptor.

Thanks, that makes sense - so 1.5A is the maximum capability, not the amount it "forces" out!

googler

HappySeagull wrote: »

Thanks, that makes sense - so 1.5A is the maximum capability, not the amount it "forces" out!

The adaptor will supply as much as the appliance demands, up to its max capability, whereupon it will show signs of stress, usually manifested by overheating first, followed by failure.

[Deleted User]

googler wrote: »

I want to connect a car tyre compressor, which normally runs off the cigarette lighter or accessory socket in the car, to a mains adapter, but the compressor is rated at 7.0A, whereas the most powerful adapter I have handy is rated at 3.0A.

Here you go.

https://www.amazon.co.uk/Cigarette-Lighter-Voltage-Converter-Adapter/dp/B00PUNIEI2/ref=pd_lpo_263_bs_t_1?ie=UTF8&psc=1&refRID=QEZB1JZPY9TKDAAYS4QT

agrinnall

I'm a bit surprised that a power problem at the router has cause there to be no phone line, is there only an IP phone?

mrmike1989

Perhaps it's not the PSU to the modem that is at fault, but rather the socket/extension that the phone and modem are plugged into.

[Deleted User]

mrmike1989 wrote: »

Perhaps it's not the PSU to the modem that is at fault, but rather the socket/extension that the phone and modem are plugged into.

Unlikely, given the OP said:-

HappySeagull wrote: »

Having been out all day, the though occurred to simply plug in another power adapter - bingo, flashing lights. :T

HappySeagull

agrinnall wrote: »

I'm a bit surprised that a power problem at the router has cause there to be no phone line, is there only an IP phone?

Yes, fibre to the premises, phone and broadband come through that.