Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Don Y Newsgroups: sci.electronics.design Subject: Re: electrical deaths Date: Wed, 27 Nov 2024 20:24:55 -0700 Organization: A noiseless patient Spider Lines: 64 Message-ID: References: <14ffkjd0l05reghi60eu47muk3kuaof23l@4ax.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Date: Thu, 28 Nov 2024 04:25:02 +0100 (CET) Injection-Info: dont-email.me; posting-host="19063625e8c029b3f93d413d6b675ef1"; logging-data="417935"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX18qPN8yEVnf1lqhlDXr0FkG" User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.2.2 Cancel-Lock: sha1:i4xVZ1bQFvDbH9zzHtqEO/IZNXk= In-Reply-To: Content-Language: en-US Bytes: 4305 On 11/27/2024 6:33 PM, Carlos E.R. wrote: > But a tea kettle or a bread toaster or the microwave plug into 120, drawing > quite some amps. Many electric tea kettles have the element IN the kettle. So, there is an EASY "mate/unmate" connection between the kettle and its base (a set of concentric rings). A small one (~1 liter) typically has a 1500W rating. A "2 slice" toaster (you can find them in 4 slice models as well) is typically 1000W. Microwave ovens are 600-1000W. Toaster ovens are 1200 to 1800W. (Belgian) Waffle iron, pizzelle iron, et ilk are in the 700-1800W range. [Keep in mind that US homes tend to have a pair of 20A (2400W) "small appliance" circuits to address countertop loads in the kitchen.] Most other "pluggable" small appliances are in the 200-600W range (hand/stand mixers, blenders, etc.) All kitchen pluggable appliances tend to be sold with short power cords (18-24 inches). As such, are plugged and unplugged typically with each use. [This leads to wear and tear on the plug and receptacle, both of which lead to increased losses IN that connection, over time.] Hair dryers are nominally 1000W. All of these are often cheap, "tinny" products -- not built very robust (save for "better quality" microwaves and toaster ovens) -- because they CAN be built "cheaply" (cost&quality) and consumers tend not to want to spend much on them. > If those connections get a bit rusty, they also get hot. And > they need thick wires; thick copper is not that easy to wrap around connectors. A 20A branch circuit (e.g., countertop services) is fed by 12AWG conductors (hot, neutral and earth). Additionally, use of receptacles RATED for 20A loads tends to lead to improves quality of that receptacle. OTOH, many are wired (by homeowners!) with "back stab" connections where the ends of the individual conductors are stripped of insulation and then then "poked" into holes in the back of the fixture where a spring-loaded mechanism grips them. This is typically not as robust as "completely" (270 degree) wrapping a conductor around a screw that causes both sides of the wrapped conductor to be in contact with the screw/terminal. Additionally, many folks "daisy chain" the inbound "feed" THROUGH the fixture to the outbound (i.e., two separate connections for each conductor on the fixture). As the fixture (receptacle) is "exercised" by the insertion and removal of plugs, small motions cause the stiff wires to loosen. If this happens at an upstream fixture, then that connection may be passing most of the current drawn on that branch circuit (instead of JUST the current used in that fixture). [A better wiring technique is to connect inbound and outbound conductors under a wire nut (sized for the number and size of conductors) along with a "pigtail" to feed the fixture. In this way, the downstream loads are firmly connected to the "feed" and only the current flowing through the fixture (via the pigtail) is susceptible to loosening AT the fixture. But, this is more labor intensive.]