1 Symptoms are due to the effects of excess acetylcholine on nicotinic and muscarinic acetylcholine receptors in the CNS, at neuromuscular junctions, and in the sympathetic, and parasympathetic nervous systems. 2  Nicotinic and muscarinic receptors have different. 3  Functions.
We're taking here about mains voltage (say 120 V or 230 V AC) power supplies with power ranging from a few Watts to several hundred Watts. Switch mode power supplies are everywhere; here are some pictures of their guts. The big high power components and small heat sinks are typical of SMPS. These devices are incredibly reliable, but being very often left powered all the time (even when their load is switched off), they still are the weak link.
Due to the wires having electrical resistance, which means that they resist the motion of electrons, the electrons bump into atoms on the outside of the wire, and some of their kinetic energy is given to the atoms as thermal energy. This thermal energy causes the wire to heat up. Electrical burns occur when you hold on to a wire, and due to heat transfer, some of this thermal energy is transferred to you. When the wires get hot enough due to a constant input of heat, there will be more heat to transfer to you if you touch the wire, and all of this excess heat can cause burns and fires.