Mains protection query

[dmccombe7]

Just curious to know if anyone uses any mains protection more so in venues with suspect sockets etc.

Was thinking of something you would plug into the venue socket and you then plug into the unit.

 

Just curious.

Dave

[JapanAxe]

I always carry an RCD plug and a ring main tester. I rarely have to use the RCD now as most venues have them at the stage socket or on the consumer unit. The ring main tester has occasionally shown up a missing earth connection, the last 2 times being on an outdoor stage and at a rehearsal studio.

[dmccombe7]

1 minute ago, JapanAxe said:

I always carry an RCD plug and a ring main tester. I rarely have to use the RCD now as most venues have them at the stage socket or on the consumer unit. The ring main tester has occasionally shown up a missing earth connection, the last 2 times being on an outdoor stage and at a rehearsal studio.

What type are you using both RCD and ring mains tester unit. Just thinking it might be worth having something

Dave

[JapanAxe]

The RCD plug is JoJo with 2 sockets which is very handy but I’ve never seen another one like it. Just make sure you get a double pole one - switches off both live an neutral when triggered.

The ring main tester is a Rapitest but there are plenty of inexpensive alternatives available.

[bassace]

Things have moved on since I used to stand on a rubber mat to avoid getting a ‘jolt’.

[TheGreek]

I use a circuit breaker - also use it at home. 

 

Same as this:

https://www.screwfix.com/p/masterplug-13a-fused-plug-through-active-rcd-adaptor/63731?tc=OA7&ds_kid=92700055281954484&ds_rl=1249401&gclid=CjwKCAjw3riIBhAwEiwAzD3TibvJqSWpV_U9XJQHvJWCVFNaoXazJhJ9SmWbsKIDts18-NItn8X8zhoCW-oQAvD_BwE&gclsrc=aw.ds

[Marvin]

Just now, TheGreek said:

I use a circuit breaker - also use it at home. 

 

Same as this:

https://www.screwfix.com/p/masterplug-13a-fused-plug-through-active-rcd-adaptor/63731?tc=OA7&ds_kid=92700055281954484&ds_rl=1249401&gclid=CjwKCAjw3riIBhAwEiwAzD3TibvJqSWpV_U9XJQHvJWCVFNaoXazJhJ9SmWbsKIDts18-NItn8X8zhoCW-oQAvD_BwE&gclsrc=aw.ds

I've got the same(ish) one. It's always in my gig bag...well, apart from when I'm using it of course

[dmccombe7]

31 minutes ago, TheGreek said:

I use a circuit breaker - also use it at home. 

 

Same as this:

https://www.screwfix.com/p/masterplug-13a-fused-plug-through-active-rcd-adaptor/63731?tc=OA7&ds_kid=92700055281954484&ds_rl=1249401&gclid=CjwKCAjw3riIBhAwEiwAzD3TibvJqSWpV_U9XJQHvJWCVFNaoXazJhJ9SmWbsKIDts18-NItn8X8zhoCW-oQAvD_BwE&gclsrc=aw.ds

And easy to buy thru local Screwfix. Liking that one.

Dave

[dmccombe7]

I have a 19" rack mounted mains surge protection unit with 6 sockets on it but i dont think it protects LIKE AN rcd. I think its more surge protection.

Problem is i'm waiting on a new Mesa TT800 and will stop using my rack with Mpulse and Korg tuner.

Dave 

[Downunderwonder]

Does a RCD still work if there is no ground?

[Woodwind]

2 hours ago, Downunderwonder said:

Does a RCD still work if there is no ground?

Good question!

 

I have played in some venues with absolutely shocking (excuse the literal pun) electrics and was worried my cut off unit like the one @TheGreeklinked to wouldn't work.

 

Just Googled now and found this on electriansforums.net:

 

"...No, an RCD does not need an earth to work, but as above, current has to "leak" out of the circuit(s) protected by the RCD for it to operate. This leakage current is at the most 30mA (0.030 amps) before the RCD trips, although a healthy RCD will trip well within that. To clarify further, leakage current is, for instance, someone accidentally (or otherwise) coming in contact with a live wire in which case some of the current will flow through such person down to the earth. The RCD will then pick up that not all current leaving the line conductor is returning in the neutral and will thence operate because of this imbalance. Hope this helps too, I tried to make it simple but not sure if I've succeeded! Cheers..."

Edited August 8, 2021 by Woodwind
spelling

[Mottlefeeder]

An RCD at the switchboard/fuseboard will not require an earth to operate correctly, but many plugtop RCDs require an earth before they will switch on.

 

David

[gafbass02]

I plugged one in at the Princess Charlotte in Leicester once back in the early 90s and it blew the power out in the entire building. By the time it was fixed, the crowd had gone and we had 20 mins left!

I ran the sound there a few times, and one of the power amps used to shoot a foot long flame out the front when you powered it up. 
Those were the days 😂

[Lozz196]

In house Pyros, awesome 

[TheGreek]

2 hours ago, gafbass02 said:

I plugged one in at the Princess Charlotte in Leicester once back in the early 90s and it blew the power out in the entire building. By the time it was fixed, the crowd had gone and we had 20 mins left!

I ran the sound there a few times, and one of the power amps used to shoot a foot long flame out the front when you powered it up. 
Those were the days 😂

 

...and they say reminiscing isn't what it was.

[BillyBass]

Electrician here.

RCDs are good, however you do need to check to see whether the consumer unit already has one for that particular socket circuit, whether as an RCD protecting that circuit’s MCB or an RCBO, which is a combination of an RCD and an MCB. Two RCDs in a circuit are a problem, you can get nuisance tripping.

 

those little socket testers are good, I use one for work.  They show up faults but you can’t rely on them to tell you the nature of the fault.  If you get the two green lights, all is good.  Anything else I.e. a red light somewhere then it’s call an electrician time.

 

Surge protection is fine, however, it will rarely be needed/used.  Faults from the sub station that would trigger an over voltage are rare and over current is covered by the consumer unit.

Edited August 8, 2021 by BillyBass

[Phil Starr]

I always plug everything into a single socket. I've had problems in the past with floating point earths. This is where different circuits in a building are poorly earthed or sometimes not at all. That leads to the earth connections of some of the wall sockets being at a different voltage to other sockets. Since the outer metal parts of our gear are often/usually connected to earth that touching the metal parts of your bass and another metal object like a mic can lead to quite an unpleasant shock. It's relatively common in old buildings but I've even had the problem in new buildings. If your own gear is all sound and plugged into a single socket you know everything is at the same earth potential. With modern gear you are really unlikely to be drawing 13 amps (3000W) so overheating shouldn't be a problem so long as your cable reels are unwound.

[skidder652003]

3 minutes ago, Phil Starr said:

I always plug everything into a single socket. I've had problems in the past with floating point earths. This is where different circuits in a building are poorly earthed or sometimes not at all. That leads to the earth connections of some of the wall sockets being at a different voltage to other sockets. Since the outer metal parts of our gear are often/usually connected to earth that touching the metal parts of your bass and another metal object like a mic can lead to quite an unpleasant shock. It's relatively common in old buildings but I've even had the problem in new buildings. If your own gear is all sound and plugged into a single socket you know everything is at the same earth potential. With modern gear you are really unlikely to be drawing 13 amps (3000W) so overheating shouldn't be a problem so long as your cable reels are unwound.

Hey Phil, is it true that so long as you don't turn everything on at the same time, ie all the PA and amps, lights etc, one socket is usually ok to run everything off with extension leads? Quite often the pubs only have one available lead especially if we're playing outside, so far we've had no issues.

[Downunderwonder]

16 minutes ago, skidder652003 said:

Hey Phil, is it true that so long as you don't turn everything on at the same time, ie all the PA and amps, lights etc, one socket is usually ok to run everything off with extension leads? Quite often the pubs only have one available lead especially if we're playing outside, so far we've had no issues.

Doubtful unless your gear is all LED lights and class D amps. Back in the day:

1 50w Marshall

1 Trace 250

1 Fender 30w SS combo

1 Peavey PA and a mixer

No lights.

Enough to blow the fuse on a 10A circuit if we got too loud!

[skidder652003]

19 minutes ago, Downunderwonder said:

Doubtful unless your gear is all LED lights and class D amps. Back in the day:

1 50w Marshall

1 Trace 250

1 Fender 30w SS combo

1 Peavey PA and a mixer

No lights.

Enough to blow the fuse on a 10A circuit if we got too loud!

Guess we've been lucky then, 100W valve Marshall, 300W D class Markbass Combo, 4 x 400W RCF 15"s, 1 x 800W Mackie 18" sub, numerous lights, moving heads, smoke machine. Not a happy bunny when it's all we're offered TBH, but as I said so far we've been lucky. Does running off several wall sockets help? I mean aren't they all connected to the same ring?

[Downunderwonder]

32 minutes ago, skidder652003 said:

Guess we've been lucky then, 100W valve Marshall, 300W D class Markbass Combo, 4 x 400W RCF 15"s, 1 x 800W Mackie 18" sub, numerous lights, moving heads, smoke machine. Not a happy bunny when it's all we're offered TBH, but as I said so far we've been lucky. Does running off several wall sockets help? I mean aren't they all connected to the same ring?

Looks like all your amps bar the Marshall are class D. That makes a huge difference in draw, still sounds a bit dodgy with that long list all running off the one lead, as much for the lead and your multibox as the outlet.

 

In our case we had to run a cord from another room on a different fuse circuit.

[Dad3353]

1 hour ago, Downunderwonder said:

Doubtful unless your gear is all LED lights and class D amps. Back in the day:

1 50w Marshall

1 Trace 250

1 Fender 30w SS combo

1 Peavey PA and a mixer

No lights.

Enough to blow the fuse on a 10A circuit if we got too loud!

 

That lot draws more than 2500w..? Something needs checking, I'd say. In our practise room, with one ring of sockets from standard (in France...) 16A circuit, we have a Hiwatt 200w valve amp, Laney 50w valve combo, Mesa Simul-class A 2x90 valve amp (and Fx rack...), a Crown 3000w PA head (plus mixer...) and my e-drums (with laptop, mixer, powered monitors etc...). Oh, yes, and a few keys/synths and their laptop and Fx etc. No surprise; it's never shown any sign of tripping, and nor it should. It may get loud, on occasion, too. Yes, we could switch it all on at once, but I don't see why we would. We have to wait for the bottles to warm up, anyway. 

Edited August 9, 2021 by Dad3353

[Ed_S]

33 minutes ago, Downunderwonder said:

In our case we had to run a cord from another room on a different fuse circuit.

I’m not an electrician, but one at work told me never to do that in commercial premises unless I was absolutely sure that both circuits were on the same phase. I got the feeling that he thought it was a pretty bad idea even then, but apparently if they aren’t and there’s a fault between two bits of kit on different phases, the jolt you’re risking hurts considerably more.

 

Same guy also told me that if you think you might get a zap from something you’re about to touch then keep one hand in your pocket (cue the music) and touch it with the back of your other hand so that if it turns out to be live, your arm naturally pulls away as your muscles contract due to the shock, and you don’t grab onto it when your fingers clench at the same time.

 

Interesting bloke to chat to 🙂

[Downunderwonder]

The place was built as a holiday home so it may have had the fridge and freezer on the same run as our amps.

[Steve Browning]

Minor derail but kind of relevant to the discussion as it's evolved.

 

If a Mesa TT-800 states it's rated at 250 watts (consumption) then the amps being drawn will be 250/230x1.4 = 1.5 amps. Is that correctly worked out? Just trying to get a feeling for the total draw of the band and the number of sockets required.

 

Does it also mean that that is with the thing running flat out? I run mine at about 3 and that's truckloads. I guess that begs the question, does running at 30% (approx) consume 0.45amps?