Electrical – Does it matter whether surge protectors share an outlet

It depends. Outlets are manufactured so that both sockets are powered from a single source - one hot wire and one neutral wire and a ground wire for safety.

On almost all outlets, those sockets are connected by small tabs of brass that feeds the connections from one socket to the other. If you attach the hot and neutral wires to the screws for one socket, these brass tabs carry that connection to the other socket. It works the same way if you use the press in connections which are holes on the back of some outlets (but many pros and DIYers do not favor using press in connections). The brass tabs on the side carry the power from one socket to the other.

You can change this. If you break off the brass tab on the hot side, the hot wire you attach to one socket does NOT carry over to the other socket within the outlet. This technique is often used to have an outlet with an always live socket (for clocks, etc,) and a switched outlet (for bedside lamps). The outlet is wired with two separate hot leads, one that is always hot and one that goes through a switch. They could be on the same or different breakers depending on several factors. The neutral side may or may not be connected depending on several factors that are not critical here.

You can also separate the sockets if you wanted a dedicated socket for a high draw device, such as a heater, and run a separate line from the panel. (This generally would require a separate neutral).

In your example, if the sockets are set up conventionally, that is powered from a single line, there is no difference, except plugging into a socket is a marginally safer approach than multiple splitters. Be sure that the overall load that is likely to be used at one time does not exceed the capacity of the surge protectors or the circuit breaker on the line.

As put in the comments, you should never put a switch in the neutral of a light.

Further, I am going to assume you are in a place where they use the wire colours as follows, because that seems the case in your drawing (I don't know all the world-wide colour schemes, but the most famous one that fits you image is this one I think):

• Brown = Phase ( = hot )
• Blue = Neutral
• Green/Yellow = Earth
• Black = Switched Phase ( = hot after a switch )

EDIT: Due to John's comment I add here, that apparently in the UK the switched wire is normally neutral colour (blue here), but with a live-colour (brown here) sleeve at each end. The remaining story most likely stays the same, with that substituted for black in the remainder.

As you can see in my list, there's a special, dedicated colour for switched wires, this is true in almost all colour schemes. In most countries dozens of pages of code can be paraphrased with:

You are not up to code if you do any of the following:

• Use different coloured wires for the same signal (as you do in your drawing: Your main light gets brown, where the same wire is blue coming from the switch)
• Use a safer colour for a less safe signal (i.e. Blue for something that is switched or black for something that is always phase)
• Use the earth colour for anything other than earth
• Use the neutral colour for anything other than neutral
• Use the phase colour for anything other than phase
• Combine low voltage DC or AC, that's assumed isolated and safe, in the same distribution channels as high voltage AC.
• Put more than X wires in a tube of size Y (X and Y differ between approval collectives and as such continents)

(often these codes are as redundant as the list above, I promise)

So, if you live in a area where my wire colour assumptions are correct, you will need to do the following to be up to the latest version of code (here in NL, for example there was a transitionary period also including Red and White as standard colours, but this has well and truly ended for new installations):

1. Make all the wires connected directly to the phase brown.
2. Make all the wires directly connected to the neutral blue.
3. Make sure the switches are all connected to the phase (with brown wires).
4. Use black wires (this is where my assumption comes in) going from the switches to the lights
5. connect the other sides of the lights to the neutral (with blue wires).

This makes you up to code, and as a bonus (partly why the code is there) you can at any point in time quickly check whether all is right, because you know which wire comes from where and connects to what and no one colour ever connects to another.