Electricians Tips from a professional electrician

[BXB]

Exactly this. The plaster to the sides of the cut out is not supported, so very weak. It can be reinforced though, using timber battens, without too much trouble:

• Cut the hole out of the lath and plaster for the backbox with multitool (we're gonna use a steel BB).
• Cut a couple of timber battens, something about 2" X 1" should do. They're going to go inside the wall, vertically, to either side of the hole, and need to be long enough to extend beyond a couple of un-cut laths, both top and bottom. About 150 - 200mm long is about right.
• Reach inside the hole, and carefully pull away the plaster 'keys' from either side of the hole where the battens are to go. We want the battens to press right up against the back of the laths without being fouled by any bits of plaster.
• Now the fiddly bit.
• Liberally coat the face of one batten with PVA, water based gripfill, or similar. Maneuver the batten through the hole and into position vertically to the side of the hole, glue side pressed up against the back of the laths. Hold in place, and drive a screw through the plaster, through an un-cut lath, and into the top of the batten. Repeat for the bottom of the batten. You can put screws through the cut laths into the batten too if you like.
• That side is now reinforced, and will be about as strong as you can hope for in a lath and plaster wall. Do the same for the other side of the hole with the other batten. You can now fix the backbox in place by screwing through the sides into the battens.
• Filler over the screw holes and you're done.

This is exactly what I do, and it can work very well. The issue I find is on very old lathe and plaster, where the use of a multitool can disturb the laths, especially when nearing the end of the cut. If the lath shakes around enough, it can detach from the plaster over a long area, leading to the plaster becoming weakened and worst case falling off (depending on how much hair has been used, and what the condition of the wall is like). I get around this by temporarily screwing the reinforcing battens to the front of the wall once the plaster has been nibbled away, picking up the laths to be cut. This binds the ends together and stops them from shaking around. I find using an old drill bit to predrill the plaster helps stop it blowing out near the edges when putting the screw in.

Lath and plaster ceilings are another matter! If you have good access, then a thin plate of plywood glued from above and screwed from below (watch the tips of the screws, mind) before using a holesaw works very well. A thin layer of PU glue or gun foam works well as it creeps into all of the voids. If you don't have good access, good luck! The reinforcing batten method does work for ceilings as well, but is trickier to apply if the downlight cut out is small diameter, so it can be worth specifying downlights that are a bit wider than normal. The other benefit of using battens/ply is that the spring arms of the downlight have an even surface to rest on, and by being a bit higher than the back of the ceiling adds some extra tension.

At any rate, I find it takes longer to carry out work on houses with lath and plaster so tend to add extra time to the costs to reflect this.

Also, lath and plaster walls and ceilings are basically a collection of lots of lovely dry timber with plenty of surface area - metal backboxes with intumescent jackets are a good approach as are fire rated downlights and hoods. Might add a few quid per point, and could be considered overkill, but you never know who is going to fart around with that outlet in the future so I consider it a good investment.

The cardboard box/masking tape method is also a favourite of mine to catch debris falling from a wall, and can also be adapted using a square of cardboard folded up at the edges with a hole in the middle to produce a makeshift holesaw debris catcher you can put over the drill before fitting the arbor. Might not look very fancy, but does the job.

 

[Intoelectrics]

Level is not always preferable.

Often you find a wall, ceiling, door/window frames etc... that are not very level. Try to follow the lines that catch people's eyes.

Nowt worse than people commenting on your work not being level until you pull out your level finder and show them that it's the building or other items that are out. So much of our works can be hidden, so the bits that are on show need to look good, I often use "rack of the eye" in these cases.

 

[Intoelectrics]

Only use hammer action on your drill when the material is hard. Tungsten tipped drill bits will drill through many materials without using hammer. Don't let them get too hot, though tungsten has a high melting point, they will melt if too hot, also the weld that holds the tungsten in place can give up at high temperatures. Pulling the drill in and out as you drill will release debris and reduce friction taking strain off your drill and also aiding with cooling of the bit.

(apologies to those of you that already know all this, I was just explaining it to one of my apprentices, so thought I'd post it here at the same time)

 

[brianmoooore]

Level is not always preferable.

Often you find a wall, ceiling, door/window frames etc... that are not very level. Try to follow the lines that catch people's eyes.

Nowt worse than people commenting on your work not being level until you pull out your level finder and show them that it's the building or other items that are out. So much of our works can be hidden, so the bits that are on show need to look good, I often use "rack of the eye" in these cases.

Nowhere is this more true than when installing conventional wet radiators under windows. Forget the level, and match the radiator top to the window sill. Can affect the choice of radiator in some cases, as you ideally need one where the air vent can be positioned on the higher end.

 

[Intoelectrics]

Nowhere is this more true than when installing conventional wet radiators under windows. Forget the level, and match the radiator top to the window sill. Can affect the choice of radiator in some cases, as you ideally need one where the air vent can be positioned on the higher end.

The problem comes when function has to take priority over aesthetics. I remember fitting a Belfast sink that looked slanted to the eye but was dead level. The customer complained that I'd fitted the sink "on the p**s". he insisted that I re-install it "level". He phoned me the day after saying the sink doesn't drain properly and puddles at one end. ?

 

[pirate]

Loving these tips, guys!
A quality stepped cone drill can also make life easier. They are cheap compared with faffing about to get the right hole in a pattress or front plate for an LED or push button...or a countersink.

 

[Intoelectrics]

Loving these tips, guys!
A quality stepped cone drill can also make life easier. They are cheap compared with faffing about to get the right hole in a pattress or front plate for an LED or push button...or a countersink.

I agree, I lost mine the other day and was frantic to find it. It's just one of those tools that you sort of fall in love with ?

 

[pirate]

and a sheet metal hole punch is a far easier way to get those 20 or 25mm holes you need without the messy drilling, and a few strokes with a deburring tool tidies up any swarfy edges on all sorts of materials. I use Noga, plenty tip choices, and a small addition to your toolbag

Deburring System

www.noga.com

 

[Mikegh]

Nowhere is this more true than when installing conventional wet radiators under windows. Forget the level, and match the radiator top to the window sill. Can affect the choice of radiator in some cases, as you ideally need one where the air vent can be positioned on the higher end.

I'm nearly sure a plumber told me rads are supposed to be fitted slightly off-level

 

[Mikegh]

Downlights when I was doing them

Leave you're wires in situ between the joists

Mark all the positions on the walls with chalk

As soon as the slabs go up drill all your holes , keep them to 50mm if unsure

If they need to be widened later you can do the trick of threading one holesaw inside the other to widen the hole cleanly

The first step saves the inevitable screwup of slabbers making the downlight holes and pulli down the cables

Probably most sparkies do it that way anyway lol, been a while since I was doing them

 

[Mikegh]

Only other thing is get used to using a voltstick

You can't prove anything with them but they will save you so much time troubleshooting

 

[Lister1987]

Downlights when I was doing them

Leave you're wires in situ between the joists

Mark all the positions on the walls with chalk

As soon as the slabs go up drill all your holes , keep them to 50mm if unsure

If they need to be widened later you can do the trick of threading one holesaw inside the other to widen the hole cleanly

The first step saves the inevitable screwup of slabbers making the downlight holes and pulli down the cables

Probably most sparkies do it that way anyway lol, been a while since I was doing them

Can't seem to do that with that Bosch prpgressor stuff with the quick change Arbor. Not tried to take them off the QC adapters yet and trying it.

 

[pc1966]

I might have mentioned this before and the post might not stay for long but a young lady was rushed to the local a&e with a vacuum cleaner nozzle firmly wedged in her ##### . However the following morning a hospital spokesman said she was picking up nicely. ?

Truth is even stranger than jokes:

Dwarf glued penis to Hoover

Metro.co.uk: News, Sport, Showbiz, Celebrities from Metro

metro.co.uk

I have seen the Circus Of Horrors show, they are quite entertaining and worth going to if doing a show nearby. Also it was not a Hoover (capitalised is trade name), but a Henry hoover.

 

[LukeD]

The tip about NOT using Hammer action is one i learnt years ago. It destroys stuff very quickly .Anything "New build " will just fall apart if you use hammer ! I also only uses wood bits when drilling plaster board .Find the holes much better . BUT ..only when i am sue no cables or pipes !

 

[Mikegh]

Can't seem to do that with that Bosch prpgressor stuff with the quick change Arbor. Not tried to take them off the QC adapters yet and trying it.

It works with standard holesaw

You thread the 50mm inside the bigger holesaw to widen the hole cleanly