Things to know before attemping DIY electrical work

[yankey-sparky]

To anyone reading this post: This a first draft and should NOT be used for reference!!!

As the forum regulars know, working on electricity is very different from working on other home repair projects. Electricity is invisible, it can start fires, and it only takes a fraction of a second to get a potentially fatal shock off the mains supply. The only other work that even comes close to this level of danger is working with gas, and you can at least smell a gas leak (usually).

Lately I've seen some disagreement on what a DIYer should know and what tools he should have before he even considers taking off the cover plate to a light switch. It is my intention therefore to create a master list of tools and basic knowledge for electrical DIY projects. A couple of lists for specific projects (such as kitchens) that require additional tools and have extra IEE wiring regulations would be helpful additions. A list of projects that the amateur has no business tackling himself might also be a good idea.

I know some of the basic information is in the "welcome" post, but it's rather scattered and disorganized, and there is disagreement therein. What I'm looking to accomplish is a maintainable, organized, single post containing as much information as possible. A forum regular who isn't planning on leaving any time soon should make this post and edit it as necessary.

If we could make the final version of this list an "announcement" style post, we could point all new DIYers to it rather than repeat the same safety information over and over in the posts, as well as make sure that they know basics like what color the neutral wire is before they start work.

Here's some suggestions from me to get started, bear in mind I'm not an electrician and I'm not from the UK, so this is just to get started.

Essential DIY Information for Electrics:

• Things to Know:
• The definitions of Voltage, Amperage, and Resistance.
• The difference between Live, Switched Live, Neutral, and Earth, and the standard wire colors of each.
• What the standard markings and abbreviations mean on electrical parts, such as "Com" and "L1". (someone help me out here with others)
• The difference between a fuse, a circuit breaker, and a residual current device.
• How to isolate the power to the area in which you will be working.
• How to use a voltmeter at the very least, a multimeter preferably.
• The minimum wire size you should be using (someone help me out here with UK regulations).
• The difference between AC and DC
• What "ring mains" wiring means and how to properly hook it up.
  Don't work on electricity unless you understand all of these terms!

• Tools to Have:
• A set of screwdrivers (do you use both Philips and flathead in the UK?)
• Wire strippers
• If a fuse is protecting your work area, have at least one spare fuse of the same Amp rating and style
• A voltmeter at least, a multimeter preferably
• Eye protection

• Safety Precautions to Take:
• ALWAYS isolate the power to your work area, either by turning off the circuit breaker or removing the fuse. Leave a conspicuous note at the consumer unit to prevent anyone from turning the power back on while you are working, and make sure everyone else knows you will be working. If your consumer unit locks, lock it and keep the key with you at all times until you are finished. NEVER work on live wiring!
• Always test the wires and connections you will be working on with your voltmeter to make sure they are unpowered. Even if you think you have isolated all the power, bad wiring or multiple feeds into the same room can cause accidents.
• Always make a note or a sketch of the wires you are working on so you know where they go. It wouldn't be a bad idea to file this away for future reference, in case something goes wrong or you need to work on it again.

1. Common Tasks in Order of Difficulty:
2. Replace an socket
3. Replace a light switch
4. Add a spur off a ring mains
5. Install a new mains power light fixture
6. Add a new socket in a ring mains
7. Replace a 2-way light switch
8. Install a new extra low-voltage light fixture
9. Add an additional consumer unit

• When You Should Call an Electrician:
• If your circuit breaker keeps tripping/fuse keeps blowing and it's not immediately obvious why.
• If you see that the existing wiring is wrong (wrong colors used, not up to IEE wiring regulations, etc).
• If you are not comfortable working with electricity, don't know all the terms in the "things to know" section, or don't have the proper tools.
• If there might be IEE wiring regulations you don't know about, for example working in the bathroom or kitchen.
• If the project is replacing the consumer unit, or working directly with the supply from the utility.

Please correct me where I have erred, and make additions! Let's make this the best single reference for DIY electrical work anywhere! And let's get the issue of whether or not a multimeter is an essential tool settled once and for all.

 

[breezer]

good idea yankey-sparkey

i apreciate your comments but as you thought there are a few amend ments (its not the 5th)

ground, over here it is called earth

1.mm / 1.5mm for lights

2.5mm for sockets on a ring

6mm for cooker

6 / 10mm for shower (depending on size)

all cable is twin and earth

shut off power= isolate power

scerwdrivers

no we have flathead and mine, not philip's (generic is cross head)

outlet is socket

local codes = i.e.e wiring regulations

 

[yankey-sparky]

I made some of the changes, but I have questions:

1.mm / 1.5mm for lights
2.5mm for sockets on a ring
6mm for cooker
6 / 10mm for shower (depending on size)
all cable is twin and earth
no we have flathead and mine, not philip's (generic is cross head)

What are the maximum fuse/breaker sizes for the wires you mentioned?
By "all cable is twin and earth" do you mean that every wire you pull to any fixture or device must have three insulated conductors wrapped in a single jacket?
What is a "mine" screwdriver head?

 

[hsiboy]

I made some of the changes, but I have questions:

1. What are the maximum fuse/breaker sizes for the wires you mentioned?
2. By "all cable is twin and earth" do you mean that every wire you pull to any fixture or device must have three insulated conductors wrapped in a single jacket?
3. What is a "mine" screwdriver head?

Hi,

1. its not a straight forward answer. Your question does not take into account many factors that are considered during an installation.
Cable sizing is a fairly complex job. you have to consider the design current and the potential fault current. You then factor in external parameters, like how the cable is to be installed, what the ambient temperature is, and if the cable is to pass through insulation. As far as "breakers" go, you need to specify what type of disconection device you are going to use. This will of course be limited to some extent by your design current. There isn't a straight forward lookup table. Thats why we have electricians

2. In the states (and most other countries) a large amount of domestic wiring is carried in conduit to the outlets. in that instance you can use singles. Over here the preferred method is to use twin+earth. so the answer is yes. There are however times when you need to run a single conductor to say a light fitting, then we would use a double insulated single cable. In the states you use white and black. over here you will find red and black. red is live over here. we are about to change the colours again, we haven't done that since 1970.

3. English humour.

Stuart.

 

[amtodd]

Does Yanky Sparky mean a low voltage light fitting, or an extra low voltage light fitting?

Does he know over here there is a difference?

 

[yankey-sparky]

Does Yanky Sparky mean a low voltage light fitting, or an extra low voltage light fitting?
Does he know over here there is a difference?

It's okay to ask me directly!

Yes, I know there's a difference. I meant extra-low voltage. It's fixed now, thanks.

 

[yankey-sparky]

1. its not a straight forward answer. Your question does not take into account many factors that are considered during an installation.

Unfortunately what I am looking for is a straightforward answer. Yes, I realize that there are a number of exceptions and odd circumstances that can creep up in electrical installations that would influence your wire sizes and breaker ratings, but the average DIYer isn't going to be dealing with those situations.

What I'm looking for is a "rule of thumb" guideline, and possibly a list of situations in which you do need to know the exceptions to the rule. After all, simply pulling 5 meters of twin and earth to spur off your ring mains for an additional hoover socket (wow, I feel so British talking like this), you wouldn't really have to worry about exessive voltage drop.

 

[amtodd]

I'm sorry Yankey-Sparky. That was me asking directly. Try me when I'm being vague.

 

[ban-all-sheds]

1. its not a straight forward answer. Your question does not take into account many factors that are considered during an installation.

Unfortunately what I am looking for is a straightforward answer. Yes, I realize that there are a number of exceptions and odd circumstances that can creep up in electrical installations that would influence your wire sizes and breaker ratings, but the average DIYer isn't going to be dealing with those situations.

What I'm looking for is a "rule of thumb" guideline, and possibly a list of situations in which you do need to know the exceptions to the rule. After all, simply pulling 5 meters of twin and earth to spur off your ring mains for an additional hoover socket (wow, I feel so British talking like this), you wouldn't really have to worry about exessive voltage drop.

I don't have a copy, but I think that's what the IEE On-Site Guide is supposed to do?

And now.....

Ladeeeez and Gennelmen....

Tonight's main event.....

"And let's get the issue of whether or not a multimeter is an essential tool settled once and for all"

Since this isn't in response to anybody asking for help with a DIY job, I don't have to be my usual diplomatic self

If you are too stupid or too lazy to learn to use a multimeter to check voltages, switch functioning, fuses etc then you are too stupid or lazy to consider doing anything with electricity apart from turning lights on and off.
Or unplug the kettle.

They needn't cost much see here

____________________________________________________________
The value of my opinions may go down as well as up. Other opinions are available. Your sanity may be at risk if you try to reason with me. If in doubt consult a professional bigot.

 

[breezer]

does that mean that some one will have to be called to unplug the kettle?

c'mon guys yankey_sparkey is only trying to be helpful, what idf he leaves out cable size

Oh and yankey_sparkey its a vacuum cleaner

 

[Scoby_Beasley]

I thought it was a Hoover. Dam !!!

 

[ban-all-sheds]

Oh that sucks.....

 

[Scoby_Beasley]

 

[hsiboy]

Unfortunately what I am looking for is a straightforward answer. <snip>

What I'm looking for is a "rule of thumb" guideline, and possibly a list of situations in which you do need to know the exceptions to the rule.
<snip>
you wouldn't really have to worry about exessive voltage drop.

I don't have a copy, but I think that's what the IEE On-Site Guide is supposed to do?

The onsite guide is none of the above. its just a logical reference. i.e they group all the regs for say EEBADS together.

And volt drop does not matter? hmm what about common sense? The next occupier may plug something larger than a "hoover" in your socket.

I recently visited a house where the owner had plugged in a search light (no, i dont know why). the socket was destroyed as was the wiring at the socket it had been spured off.

Oh, and i dont think that multimeters are that great. A neighbour once asked to borrow mine. He hurt himself when he set it to current measuring and stuck the test probes accross P&N. Had he told me what he was doing i would have advised him
a) how to measure current, and
b) lent him another meter (clamp).
c) given him fused leads for it.

Stuart.

 

[yankey-sparky]

And volt drop does not matter?

Well, don't take me out of context. But for a short run I wouldn't think you'd have to worry about it.

hmm what about common sense? The next occupier may plug something larger than a "hoover" in your socket.
I recently visited a house where the owner had plugged in a search light (no, i dont know why). the socket was destroyed as was the wiring at the socket it had been spured off.

This is why I'm asking about the ampacity limits on conductors. This situation would not have come up if the wires were sized properly for the breaker that was protecting them. If it was, the breaker would have tripped before the wires and socket were damaged. This is essential DIY information that I'm trying to include here.

In the US, we generally use 14AWG (2.5mm^2) for 15A breakers and 12AWG (4mm^2) for 20A breakers. I'd like to know what you generally run for UK breaker sizes, which are much larger than typical US breakers, and how the ampacity limits compare to US limits.

On that note, what are your sockets rated for?

Oh, and i dont think that multimeters are that great. A neighbour once asked to borrow mine. He hurt himself when he set it to current measuring and stuck the test probes accross P&N.

This is why I included knowing how to use a multimeter in the "things to know" section. Yes, you can get hurt if you don't know what you're doing, but multimeters do come with instruction manuals. For those who don't want to bother reading the instructions (I can hear Ban-All-Sheds screaming already), a voltmeter might be safer and still do most DIY tasks.