Wiring Outlets: Backstab Or Screw?

[T_Dog]

I've never seen an actual failure of a back-stabbed outlet, but there seems to be a lot of controversy on this if one does a web search. Have already decided to use the screw terminals for the kitchen outlets where currents are high, but the rest of the house sure would get wired faster by using the push-in holes, otherwise known as back-stabbing. Curious as to the opinions (and actual experiences) of those building and involved in the electrical trade.

[Crossy]

If you had asked this 2 years ago there would have been only one answer, "No Way".

However, things have changed. Spring terminals such as are found in Wago terminals are gaining acceptance in the UK, indeed they are the only type of connector that is defined as 'Maintenance Free' for use in inaccessible locations. I have specified Wago connectors in place of taped joints or the rather better wire nuts when wiring our new build.

Whether I would use locally manufactured outlets and switches I'm not so sure, quality of the spring contacts is vital for these connections to remain reliable and safe.

I think you are on the right track, keeping screw terminals in the kitchen and only using the push type in low current, readily accessible locations.

Is there a cost advantage / penalty for the items themselves?

[T_Dog]

If you had asked this 2 years ago there would have been only one answer, "No Way".

However, things have changed. Spring terminals such as are found in Wago terminals are gaining acceptance in the UK, indeed they are the only type of connector that is defined as 'Maintenance Free' for use in inaccessible locations. I have specified Wago connectors in place of taped joints or the rather better wire nuts when wiring our new build.

Whether I would use locally manufactured outlets and switches I'm not so sure, quality of the spring contacts is vital for these connections to remain reliable and safe.

I think you are on the right track, keeping screw terminals in the kitchen and only using the push type in low current, readily accessible locations.

Is there a cost advantage / penalty for the items themselves?

Thanks Crossy....I am using the Mitsumi outlets and Panasonic switches. The Mitsumi's look to be the same quality as the Panasonic outlets at 40% of the cost. The only cost penalty is the time it takes to bend the wire around the screw terminal and tighten it down. I am thinking I will just take my time and use the screw terminals on all connections. Peace of mind as long as I remember to tighten each one!

[Greenside]

You think the Panasonic backstab type are inferior? As far as I could see, all the outlets available here are that kind of fixing. First time I saw one was when I was disassembling a power socket and I spent ages looking for the grub screws so I could get the wires out! All our outlets are of this type....

[T_Dog]

You think the Panasonic backstab type are inferior? As far as I could see, all the outlets available here are that kind of fixing. First time I saw one was when I was disassembling a power socket and I spent ages looking for the grub screws so I could get the wires out! All our outlets are of this type....

No.... not inferior, but lots of controversy if you do searches. The Mitsumi's I am using have both screw and back stab, so can do either. I am pretty sure the Panasonics are the same way. I liked the Panasonics, but I could see no real difference between them and the Mitusumi units except for the price.

[electau]

Known as insulation displacement type terminals. They are an option to use instead of screw type terminals. Clipsal (Aust) have had them on there 10A outlets since 2004 as an optional product to the standard screw version. The time taken to teminate a socket outlet is less than if a screw type is used. Might be important if you are an electrical contractor terminating a large number of outlets in an installation.

IMO the screw type terminal is preferable.

[Litlos]

Known as insulation displacement type terminals. They are an option to use instead of screw type terminals. Clipsal (Aust) have had them on there 10A outlets since 2004 as an optional product to the standard screw version. The time taken to teminate a socket outlet is less than if a screw type is used. Might be important if you are an electrical contractor terminating a large number of outlets in an installation.

IMO the screw type terminal is preferable.

Think you may have the wires crossed on this one. The insulation displacement type are like the Krone type used for communications wiring where the still insulated wire is pushed betwen two metal stakes and the stakes cut the insulation to make contact with the metal of the wire. The Panasonic type here are the spring type, I bought one of these as a replacement the other day, would have returned it/bought another but I was on my way to the airport and the outlet failed just before I went.

Personally I will not specify the spring type as I have had to many problems over the years with them. If the wire is misaligned or under tension the contact may not be good and it becomes a point for an intermittent fault. On high current if it does not get a good contact with the wire heating occurs, heating affects the sping and the spring loses tension, which causes more heating, eventually leading to failure. As I had to use the Panasonic I was very careful on wiring alignment, no problems so far. However installed by Somchai the sparkie?????

I know all the theories and sales info on how the spring type are better, just hands on experience is different.

If the Mitsumi are much cheaper than the Panasonic then there is a good chance that the build is not exactly the same. Maybe the difference is in the quality of the metal for the spring, so possibly an area for accelerated failure. Remember there is no such thing as a free lunch, and sometimes quality is not fully assesable by a mark 1 eyeball, so tread carefully and work on about a 20 year service life for a good quality fixture compared to the potential early problems of a sub quality fixture.

Cheers

[Crossy]

Litlos, Yes I was understanding that they are the spring type, strip first then push in. I don't think I'd trust any form of IDC on power circuits, the contact area is just too small.

Electau. Are the units available in Oz actually IDC (no stripping) or the spring type (strip the wire)? If they are IDC how's the reliability over time?

[electau]

I used 10 of them as a trial in 2004. Clipsal 2000 series. was not impressed with them. Screw type terminals were preferred. never used them again. There are terminals displacement type with a punch down tool for power control circuit connection made by Krone.

Yes one had to strip 13mm of insulation and insert wire, 2 wires per fitting.(loop in / loopout)

[Crossy]

Wow ^^^, those 2000 Series quick-connect are true insulation displacement connectors.

I wouldn't trust them on anything other than phone lines, that said I'm an old fart who doesn't really trust anything other than screw terminals with a nice large contact area..

[Artisi]

I used a combination, screw type on all power points and push-ins (after stripping the wire) on the light switches - fingers crossed on the light switches as this is the first time I have used them.

[Crossy]

I used a combination, screw type on all power points and push-ins (after stripping the wire) on the light switches - fingers crossed on the light switches as this is the first time I have used them.

At the sort of currents expected in lighting circuits I doubt you'll have any issues. Don't tell me you have 3.5kW of lighting on each switch

[Artisi]

I used a combination, screw type on all power points and push-ins (after stripping the wire) on the light switches - fingers crossed on the light switches as this is the first time I have used them.

At the sort of currents expected in lighting circuits I doubt you'll have any issues. Don't tell me you have 3.5kW of lighting on each switch

Nope - just standard light circuits.

[David006]

Known as insulation displacement type terminals. They are an option to use instead of screw type terminals. Clipsal (Aust) have had them on there 10A outlets since 2004 as an optional product to the standard screw version. The time taken to teminate a socket outlet is less than if a screw type is used. Might be important if you are an electrical contractor terminating a large number of outlets in an installation.

IMO the screw type terminal is preferable.

They are known as IDCs in the telecom sector and need a punch down tool.( splayed "V" or circular cylinder type which can be used for stranded wire)

In electrical outlets they seem to be just spring loaded and don't actually displace the insulation as such... just in case some DIYer tries to "stick in an insulated cable.

Not trying to rain on your parade , just thought I would point that out....

In my reno' efforts in OZ the outlets had both options which was good for applications where you have more than two cables.

Such a pain here if joining a plug or switch when you need to have more than two cables terminating..making additional outboard connections in a conduit box with a bunched up lump of inflexible solid conductors which hinders the fitting of the fitting..what a pain!!

Had a few smaller gauge wire connections fall out when fitting outlets .....from the stress I guess..

Would recommend the op try to source switches and outlets with both options..good luck Gungadin if ya can.

[Crossy]

They are known as IDCs in the telecom sector and need a punch down tool.( splayed "V" or circular cylinder type which can be used for stranded wire)

In electrical outlets they seem to be just spring loaded and don't actually displace the insulation as such... just in case some DIYer tries to "stick in an insulated cable.

Not trying to rain on your parade , just thought I would point that out....

The Clipsal 2000 series are true IDCs, no stripping. IMHO they are scary, think of all the arcing potential if they've been re-used a few times

[electau]

They are known as IDCs in the telecom sector and need a punch down tool.( splayed "V" or circular cylinder type which can be used for stranded wire)

In electrical outlets they seem to be just spring loaded and don't actually displace the insulation as such... just in case some DIYer tries to "stick in an insulated cable.

Not trying to rain on your parade , just thought I would point that out....

The Clipsal 2000 series are true IDCs, no stripping. IMHO they are scary, think of all the arcing potential if they've been re-used a few times

There has been no reported problems with them, socket outlets are generally used only once, when they are installed, they are not reused in another installation.

　

Edited March 4, 2012 by electau

[Crossy]

There has been no reported problems with them, socket outlets are generally used only once, when they are installed, they are not reused in another installation.

Add, 'in Australia'

EDIT I note that Clipsal state that these connectors may be re-used and pass the Aussie safety standards.

Still not likely to use them mind.

[David006]

There has been no reported problems with them, socket outlets are generally used only once, when they are installed, they are not reused in another installation.

Add, 'in Australia'

EDIT I note that Clipsal state that these connectors may be re-used and pass the Aussie safety standards.

Still not likely to use them mind.

lol.... think I might look at the spec and install instructions some time when a little sober...hey things change...still prefer screw terminals and still like the high contact mechanically strong wire nuts...just me...

remember all the fuss on wire wrap terminals.... minimum x turns and x ounces min of release per tension gauge or the acceptance engineer who would insist on solder if not up to some @#$%^& ... spec....

..bugger it .....how much latex we get today my sweet???

HAVE GOOD ONE GUYS....

[wayned]

I've used various manufactrues of outlets and switches available localy, national, panasonic, etc. All were strip the wire, put in the back and cinch down with a screw on the side. Never saw back stab only or twist and screw. The only problem I saw was that the wire size of the loop through had to be the same size otherwise there was poor connection. Doubled up on the smaller wire, no problem. Live in the sticks so don't have a lot of options. Built two houses in the US a long time ago, all were back stab, no screw. Think that I actually prefer the local version as you have increased surface contact area and have postive control of amount of tightening force.