Wikipedia:Reference desk/Archives/Miscellaneous/2015 June 16

= June 16 =

Kegs vs. Cans
While having dinner with some friends last night, someone said that an unopened can of beer would float. This led us into a short conversation about the difference between kegs and cans of beer. Not the taste but the physical differences. I've done some Googling and have found some information about the taste and the difference in pasteurization (kegs aren't while cans are, unless you read our article on draught beer which contradicts everything else I've read thus far).

The question remains though, is there a physical difference as far as the way they are filled and sealed, more specifically with how they are pressurized. This is what I understand thus far. Please correct me if I'm wrong and let me know if I'm right about any of it, please.


 * Cans have CO2 (and possibly nitrogen) in them under pressure.
 * Kegs have the same CO2/nitrogen in them but they also have a pump to keep the pressure up in order to be able to get the beer out.

So, essentially, there is no difference between the two, right?

BTW, the first sentence of the second paragraph of Draught beer is a fragment. Thanks, Dismas |(talk) 13:51, 16 June 2015 (UTC)


 * I suspect that the reason unopened beer cans float is because they aren't filled to the top with beer. If they were, they would spill when you opened them.  The gas at the top makes them float.  If they were completely full, then the beer would have about the same density as water, and the aluminum in the can would make it sink.  StuRat (talk) 15:17, 16 June 2015 (UTC)


 * Keg beer would normally be pasteurised in the UK, one of the reasons that the Campaign for Real Ale was successful in winning people away from it, and I'm pretty sure that keg lager all over Europe would be pasteurised, except perhaps for some microbrewery beers. Itsmejudith (talk) 15:46, 16 June 2015 (UTC)
 * Agreed: in British terms, "keg beer" generally means pasteurised and carbonated, whereas "cask conditioned" means unpasteurised with the internal pressure being provided by the ongoing fermentation ("real ale"), even though the actual container is usually the same. Note that alcohol is less dense than water so it adds to the overall buoyancy, but I suspect that the main agent is the carbon dioxide which is in suspension until you open the can. Some canned ales and stouts have a widget which makes the texture more like draught beer (and that floats too). Alansplodge (talk) 12:23, 17 June 2015 (UTC)

Why don't hotels abolish checkout and take the money from credit cards using CNP transactions?
When I stayed in a hotel a few weeks ago, I did a checkout using CNP because I had forgotten the PIN of the card I wanted to use. That was possible, you just give the card to the front desk employee and he/she will type the card number in the machine and proceed with the usual CNP transaction. I asked about that a few days earlier and they checked that someone who is authorized to charge cards this way would be present.

I then wondered why hotels in general have a checkout routine when they can always charge cards using the CNP procedure later using the card that was used to reserve the hotel with? That would save a lot of time for the front desk employees and the guests who can just pack their bags and leave without having to stand in line at the front desk. Count Iblis (talk) 14:32, 16 June 2015 (UTC)


 * Since I don't work in the hotel or credit card industry, I'm going to guess from my Googling that CNP means "Card Not Present". That said, this is the way it's been done in quite a few hotels that I've stayed in over the last 5 years or so.  When I wake up on the day of my checkout, there is a bill that has been slid under the door.  On it somewhere it explains that these charges are going to be made to the credit card on file and that I can just leave the card keys on the nightstand.  In the same time frame, I haven't gone to the front desk to check out except in a handful of cases.  Dismas |(talk) 14:40, 16 June 2015 (UTC)


 * 1) One obvious problem is that if you don't check-out they don't know when you are gone. They could just wait until check out time, knock on the door, and enter if you don't answer, but this has some problems.  You might not hear them if you decided to stay another day or check out late, and are asleep, or in the shower, or on the toilet.  Also, if you leave early they would like to know this, so they can clean the room early and have in ready for early check-ins.  They could have some type of switch you flip in the room to indicate you have checked out (maybe dial some code on the phone).


 * 2) And check-out is a good time to resolve any disputed charges. Let's say you were charged for a bottle of champagne you didn't get.  They can send down the person who delivered it and he can say "No, that's not the person I delivered it to, I must have put down the wrong room number".  Hard to do this once you have left.  And when you do sign that credit card receipt, that makes it much harder to dispute the bill later, which they like.


 * 3) Check-out is a good time to get guest feedback. Yes, they can have cards to fill out in the room, but many people won't bother with those, who will give an opinion in person.  I just did so when checking out a couple weeks ago.  Now they know their freezer doesn't freeze, phone doesn't work, and they have bugs in the bathroom, so they can fix this for the next guest.  StuRat (talk) 15:09, 16 June 2015 (UTC)
 * Some hotel chains don't have checkouts, typically in the budget ranges. The Accor group, one of the world's largest, would have checkouts in their mid market hotels like Mercure but none in Ibis Budget or Formule 1. It would be the same with some of their competitors in Europe. Itsmejudith (talk) 15:34, 16 June 2015 (UTC)
 * This might work in the US, but in Europe, where most people are sensible and use debit cards or cash, you'd still have to be there to put in you PIN. Having said that, most hotels I stay in these days I prepay anyway. 82.21.7.184 (talk) 08:30, 17 June 2015 (UTC)
 * Debit cards are "sensible"? Since when? You're just begging to be hacked and have your bank account drained. ←Baseball Bugs What's up, Doc? carrots→ 08:55, 17 June 2015 (UTC)
 * Debit cards are no less secure than credit cards. You still have to know the PIN to use them. --Viennese Waltz 08:57, 17 June 2015 (UTC)
 * Getting the pin is child's play for either kind. The difference is that your own money is more vulnerable with a debit card. ←Baseball Bugs What's up, Doc? carrots→ 09:05, 17 June 2015 (UTC)
 * Erm what on Earth are you talking about? Credit card fraud is rife here, whereas debit card fraud is very rare. It is by no means 'child's play' to get a PIN, how do you propose to do this? Your money is pretty much utterly safe with a debit card unless you're a complete numpty. Guess the rules may be different in the US. Besides, I just buy things when I have to money to do so, credit just seems like a waste of money to me. It's called financial prudence. Fgf10 (talk) 17:42, 17 June 2015 (UTC)
 * Typically the PIN is embedded in the card's magnetic stripe, right? ←Baseball Bugs What's up, Doc? carrots→ 08:15, 19 June 2015 (UTC)
 * No. --Viennese Waltz 08:29, 19 June 2015 (UTC)
 * That's a strange intervention. I'm in Europe and I use credit cards all the time.  If your belief that use of credit cards is not sensible is because you think people should not be running up credit, well I usually pay my cc bill off in full each month, and besides a credit card is a useful way of spreading the cost of large items of expenditure.  Plus, I frequently travel abroad on business, where my debit card is useless and I have no wish to carry around great bundles of cash.  --Viennese Waltz 08:53, 17 June 2015 (UTC)
 * In Britain the point about credit cards is that if the merchant with whom you contracted lets you down you can get your money back from the credit card company. 5.150.92.19 (talk) 08:49, 19 June 2015 (UTC)

12 volt wiring. How to do a T join.
Are there any decent guides or videos out there on how to wire a T. I can't seem to find many. The semantics are difficult, but I dont want to join two wire ends. I want to join one wire end on to an existing unbroken wire.

Mind you I dont have a solder, so some type of connector or clever wiring would be ideal.


 * This appears to be how it's done manually: T-splice. (They omitted covering all the exposed wiring afterwards with electrical tape (they just said the connection), but that seems like a reasonable precaution.)  They said to solder it together, but I've done splices with just braiding and tape.  It's important to have a long length of braiding, to increase the contact area.  Otherwise poor contact can lead to sparking and heating.  StuRat (talk) 19:33, 16 June 2015 (UTC)
 * There are splice-crimp connectors, such as this one (the first I found on a web search; I have no options on the manufacturer nor retailer). They allow two wires to be electrically spliced together, with only a pair of pliers, and a steady pair of hands. Simply place the connector over the middle of one wire, and the end of the other. You will need to buy the appropriate sized connector for the diameter of the wire you are splicing. LongHairedFop (talk) 20:20, 16 June 2015 (UTC)
 * They're called "Scotchlok" connectors in the UK (a genericized trademark - the original Scotchlok™ connectors are made by 3M). However, Scotchlok redirects to Twist-on wire connector, without being mentioned on that page - the redirect may be wrong (Insulation-displacement connector might be a better target, in default of an article on this specific type of connector), or "Scotchlok" may be used somewhere else in the world for a brand of twist-on connectors; asking for a "Scotchlok connector" in the USA may therefore not prove successful. Tevildo (talk) 22:35, 16 June 2015 (UTC)


 * A generic name would be I.e. "Quick Splice Terminal"; or search auto part stores for "wire connector" and you'll find them.--TMCk (talk) 00:29, 17 June 2015 (UTC)
 * "T-tap" is another common term, that's what I found them as when I was doing a wiring project on my car to splice one wire onto another without actually cutting the second one. See here for example. All you do is strip off a bit of the wire you need to tap into, jam that into the metal tab, close the plastic case, then crimp the connector it comes with on the end of the other wire and hook it up. Works great. RegistryKey(RegEdit) 08:54, 19 June 2015 (UTC)


 * Don't strip off any insulation as it will weaken the tensile strength of the wire.--TMCk (talk) 00:53, 20 June 2015 (UTC)


 * @--TMCk The bit of wire that the T-tap wraps around needs to have insulation stripped, otherwise there's no metal-to-metal contact to complete the circuit. See here and here. Those shown claim they automatically strip the needed insulation around the contact to expose the bare wire, but in my experience that didn't happen and I had to strip some insulation off then clamp on the connector to make my circuit work. As to tensile strength, this is an electrical connection, why would you be putting physical loads or moving stresses that would change tension on a piece of electrical wire to begin with? RegistryKey(RegEdit) 06:26, 20 June 2015 (UTC)


 * Yes, they're meant to work w/o stripping and if they don't work well they are of low quality, the wire is the wrong size or kind, or a combination of these. If that's the case, you should only shave off part of the insulation on the two sides where the V-slice will cut in. There are "moving stresses" on vehicle wiring, most damaging  are vibrations and driving thru bumps in the road. There is a reason why automotive wiring is not the same as your common house wiring (even in low voltage applications) and is not limited to being oil resistent: Your house is (usually) not moving ;) --TMCk (talk) 22:34, 20 June 2015 (UTC) BTW, pinging is not working when you add it after you already signed your post.--TMCk (talk) 22:34, 20 June 2015 (UTC)


 * Also note that electrical tape provides support for the wires, too, just as the original insulation did. StuRat (talk) 17:08, 20 June 2015 (UTC)


 * What tape???? There is no tape!!! You don't use tape with them!!!!--TMCk (talk) 22:34, 20 June 2015 (UTC)