Xjyuk

Power supply units will often be greedy and block access to adjacent outlets in a power bar.

A simple solution is to use 1/2 ft or 1 ft (15cm, 30cm) power extension cords to keep all outlets in a power bar available.

Yet my hunch tells me that doing so increases the fire risk.

Could someone with actual knowledge in the matter pitch in with an opinion?

Does unblocking power bar outlets through short extension cords increase fire risk?

I am not considering an exotic setup (daisy chaining, forking, etc..), nor will the wattage be high (laptop and paraphernalia, at most a stereo amplifier in one slot). The question is whether this increases the risk of fire. The idea is that there are now many more places where rust, or just a poor contact, will happen. And rust/poor contacts cause heat that can spiral to something sinister.

Update

I marked Isherwood's answer right, but thanks to Harper's and Owain's answers I see now that there is an abundance of options to avoid even a small increase in risk. One key keyword is "metal". Search, for example, for "metal power strip" to see ones where right angle plugs will not occlude adjacent outlets. Some have a larger inter-outlet spacing. The challenge is find one not painted yellow.

Yes, but negligibly.

Any connection increases fire risk by increasing the chance of heat buildup due to resistance, sparks due to arcing, etc. The question is how much, and the answer is not much.

Since you already probably have dozens of such connections in your home (including such high-current things as a microwave and kitchen range), and since most of these are low-current devices, I see no reason to be concerned.

One caveat would be the potential for heat buildup around the transformers. They're normally held captive by wall outlets or power bars and not likely to end up in a heap on the carpet. In combination, many transformers without good cooling airflow could overheat. Don't let that situation arise.

Make sure all hardware is in good working order and be happy.

In fact, there are UL-listed power strips that provide an octopus of short cords-on-sockets. (by the way it was hell to find a genuine UL-listed unit of good provenance from Stanley; most of the Amazon listings are cheap Cheese junk off the Amazon marketplace.)

It depends

If it's blocky because it's a wall-wart style transformer, then normal loads simply won't allow it to get warm enough. Wire heat is a function of power squared, so a 10-watt power block makes 1/10,000 the wire heat of a 1000 watt air conditioner.

However, if it's blocky for some other reason, like an in-cord GFCI for a heavy draw appliance like an air conditioner or hair dryer, that's a no-go. Don't even connect such a load to a power strip in the first place - it should only go either a) direct into the receptacle, or b) straight from the receptacle to the appliance via a 1-socket heavy 12 AWG appliance-grade extension cord.

Quick test question: Which draws more power: a 75 pound, 10,000 BTU wall air conditioner? Or a common hair dryer?

The air conditioner is typically 800 to 1200 watts. The hair dryer, like most cheap resistive-heat appliances, is almost always 1500W or more. Both are too large for power strips. Point being, a "high power" appliance isn't necessarily obvious. A good measure, though, is they make a fair bit of heat.

The problems of 'greedy' power supplies can be resolved by using power bars which have proper individual sockets for each position. They also tend to have better quality contacts than the cheap multi-way strips.

from

https://olsondirect.co.uk/oldsite/13a_standard_flat.htm

They also do USA standard ones, eg

https://olsondirect.co.uk/oldsite/usa_15amp.htm