Combining wires

The item "wants" 18 gauge wire? Why don't you ask it its feelings about working with 24 gauge wire? Stress to it that change is good, that we all need to adapt to challenging economic times, that there's a Chinese item out there itching to to the same job with only 28 gauge wire - you know, the usual management skills. Perhaps your item will then consider that it wants to work with 24 gauge wire.

The answer is of course " Maybe". This isn't really an engineering question - why wasn't the right size wire installed in the first place? Have you done enough analysis and do you understand the application well enough to guarantee to your client that the proposed botch-up will actually work? What is your professional liability exposure here? If it comes down to a lawsuit, can you show you've exercised enough due diligence to protect yourself from allegations of professional incompetence?

If you've managed to build a 36 story building with every office wired with the wrong cable, I suggest you obtain legal advice.

However, if you're another hobbyist wondering if his newly-invented automatic Internet-controlled squirrel proof bird feeder is going to work, the answer is of course "Try it and find out".

Bill

(who's getting tired of trying to be a mind reader on the news groups... "I've done something that I don't understand, please tell me it will be all right under all circumstances which I don't know about.")

If it is a device that should be connected to a Cat5 cable then it will work happily on a standard Cat5 cable.

What the devil is your application that wants Cat5 but does not understand what Cat 5 is??

Clue ---- Cat 5 is for Ethernet SIGNALS and no serious current so the wire gauge should not be a concern and is not if it is a CAT5 complient device.

-- John G.

To a first approximation, the wire diameter doubles for every change of

6 in AWG, while current carrying capacity doubles for every change of 3. So 18 AWG has 4 times the current capacity of AWG 24, and four wires of AWG 24 in parallel should be equivalent to AWG 18. in DC current carrying capacity. AC characteristics like capacitance and inductance depend on exactly *which* wires you tie together to make your 18-gauge equivalent wire.

Dave

And it's only rated for LOW voltage!

In the UK "Low voltage" means 'not exceeding 1000v ac or 1500V dc between conductors'. I suspect you mean "extra low voltage" - 'not exceeding 50v ac ..'

On Wed, 23 Jan 2008 13:33:13 +0000 (GMT) charles wrote: | In article , | Stuart wrote: |> In article , |> John G wrote: | |> > Clue ---- Cat 5 is for Ethernet SIGNALS and no serious current so the |> > wire gauge should not be a concern and is not if it is a CAT5 complient |> > device. | |> And it's only rated for LOW voltage! | | | In the UK "Low voltage" means 'not exceeding 1000v ac or 1500V dc between | conductors'. I suspect you mean "extra low voltage" - 'not exceeding 50v | ac ..'

The boundaries of low voltage vs. high voltage (and maybe even medium voltage) vary depending on the type of usage. Electric utilities will refer to 240 volts as low voltage because they never deal with things at 12 volts. Lighting systems will refer to 12 volts as low voltage and 120 volts as high voltage. The context needs to be established for a correct understanding of "low" vs. "high" for voltage.

Erm, no, not for those in the electrical engineering profession* in the UK. "Low voltage" is a definition, not open to interpretation depending on the application.

*and this is an electrical engineering newsgroup.

It is extremely dangerous to misuse these definitions. In electrical engineering terms, in the UK, 12v is *never* correctly described as "low voltage".

Just as "very low frequency" is precisely defined for communications engineering. 100kHz may sound like a very low frequency to an rf engineer - but it would never be described as such. Neither would 2400Hz.

I used to have a constant arguement with a colleague about the usage of

5MHz. To me, with a tv studio background it was baseband - to him, a transmitter engineer, with a short wave bias, it was rf.

VLF was shore to submarine communications frequencies or the carrier frequency of MSF.

R4 Droitwich was classed as LF at 198kHz

And to me - another transmitter engineer who, before retirement was repairing SHF links, it's slowly varying DC :-)

Yes, thank you Charles, I am aware of the differences, just talking "loosely". Not sure that the OP would be aware hence the capitalisation of the word low to emphasise the fact.

Not sure what he is considering doing but I suspect he is somewhat lacking in knowledge of electrics and where he is, the terminology may be different to the UK anyway.

I could say I have been an "authorised person" for the purposes of the HV switchgear rules but would anyone outside the UK know what that meant?

During WWII, there was a term, UHFI, which I believe originated in the UK. It was: Ultra High Frequency Indeed

In the US we also used to have a class of people called "millionaires". Until about 2004 these were relatively wealthy individuals with retirement savings. Today these same folks are considered "middle class" and when they "retire" you will likely be greeted by them as you enter a Walmart store. You can't miss them wearing their blue smock.

Actually it is 30v if you are talking about the NEC article 725 and

600v if you are using the NESC (utilities)

There is a risk that an engineer used to one set of defintions could get a nasty shock, literally, if he came to the UK and took up a job working on "low voltage" systems..Unlikely though, as most engineers that have lived long enough to be called "experienced" ...always double check.

Having written that, as a young apprentice I very nearly had several experiences of a lifetime..I tend to check three times ever since.

-- Sue

| Erm, no, not for those in the electrical engineering profession* in the | UK. "Low voltage" is a definition, not open to interpretation depending | on the application. | | *and this is an electrical engineering newsgroup.

So classify each of the following voltages according to the UK definition:

24 volts 240 volts 2400 volts 24000 volts 240000 volts

| It is extremely dangerous to misuse these definitions. In electrical | engineering terms, in the UK, 12v is *never* correctly described as "low | voltage".

I'll remember that in case I ever visit UK.

| Just as "very low frequency" is precisely defined for communications | engineering. 100kHz may sound like a very low frequency to an rf | engineer - but it would never be described as such. Neither would 2400Hz.

I've never seen any such standard with regard to voltage. Of course, I've not been in UK since ... ever.

| On Wed, 23 Jan 2008 21:07:31 -0500, **THE-RFI-EMI-GUY** | wrote: | |>Here in the US "Low Voltage" is 60 volts or less. This means that you |>won't get fried working with "Low Voltage" wiring | | Actually it is 30v if you are talking about the NEC article 725 and | 600v if you are using the NESC (utilities)

The US isn't following UK standards. We haven't for over 240 years.