RCD protection for portable equipment with Inverters

[Darkwood]

No problems. Saved us a lot of headache. A mate worked for the then competition and they were using the same drives and having the same problems we were. Over a beer one night it came up and I mentioned our fix. Turns out they had changed their make of drive totally (to Toshiba I think). It was a bit of a pain as their engineers had to learn new bit of sofware for doing the motor start ups etc. Also they kept with the original motor make which meant entering a lot of parameters manually rather than just telling the drive what motor it was running from an pre-loaded list. Think we got our Si RCDs for about £50 a time. If I think of it I'll dig out the invoice and PM you the exact type we used.

Appreciate it as ive built some portable drive kits to a company so they can do onsite repairs to machinery, they are 1ph to 3ph but we are clashing with their customers who either have rcd's tripping with our drives or asking us to fit rcd protection to units to allow to be used on site, at presence i just built in extra safety via monitored earth trip and earthed braided cable to reduce risk of shock. Funny thing is im always chatting to tech' at Sneider but never thought to ask as was unaware a device existed. Cheers

 

[gerard]

Gerard, if you are so worried about earthing of portable equipment then maybe you should look at earth proving outlets.

I have thought about this and I will probably give it more consideration

 

[gerard]

Clicon357 - can you PM the manufacturer to me also please?

 

[silva.foxx]

SEW are German and it stands for "Süddeutsche Elektromotoren Werke"

SSB are the other Krautfit I can think of.

What's with all the Secret Squirrel ****e and Masonic PM whispers anyway... they're major manufacturers within our game, just like the mentioned Scheider, Merlin Gerin and IMO Jaguar.

Is there a product placement gagging order in place?

 

[clicon357]

SEW are German and it stands for "Süddeutsche Elektromotoren Werke"

SSB are the other Krautfit I can think of.

What's with all the Secret Squirrel ****e and Masonic PM whispers anyway... they're major manufacturers within our game, just like the mentioned Scheider, Merlin Gerin and IMO Jaguar.

Is there a product placement gagging order in place?

Fair comments. My fault that I just didn't want anyone to be seen in a negative light. Anyway, it was then SEW. Hasn't stopped me using them for about 11 years now and nothing but good service from them on all fronts.

p.s. Love your tag line!

 

[netblindpaul]

silva,
I honestly thought that SEW had been bought out by a Yank outfit!
That was why I asked, I did not know why the stars, but, clicon obviously had his reasons.

 

[gerard]

Guys, guys - the ************* don't matter to me, I think I have an answer to the original problem. I an going to contact Merlin G about their 'Si' range and hopefully it will solve the whole Inverter/RCD saga? I will post my results (good or bad) as soon as I find out, so watch this space!!

 

[silva.foxx]

Anyway, it was then SEW. Hasn't stopped me using them for about 11 years now and nothing but good service from them on all fronts.

I believe all manufacturers have good and not so good points. They're all out there so should be mentioned where necessary. We've no need to protect IDs. Everyone on here is sure to have different experiences of good and bad service from these companies. I agree its wrong to bad mouth businesses but its also wrong to hide details from fellow users.

I like SEW and IMO. Both have served my chosen profession well. We use both and both are superb in my eyes.

Good info for Gerard, though. Good input. :aureola:

 

[silva.foxx]

Hi,

I know this has been covered before and I don't mean to repeat questions. I am looking to get some opinions on a problem I have encountered in the past and have experienced recently. I have a machine with two 3ph motors which are controlled by Inverters. They are 1ph - 3ph Inverters. The problem is they keep tripping the RCB. I tried putting a 100mA RCBO on the circuit, with no success. For this reason, I have taken the RCD out of the circuit and is now only protected by a MCB. I feel very uncomfortable with this and I am looking for similar problems you have encountered and how you solved the problem? The regs do not cover such equipment with Inverters and their protection.

Thanks

Why a 1ph-3ph inverter when supply is 3ph? Or is it on 1ph supply?

 

[clicon357]

Just looked at the invoice for the units we used it simply says:

"23332 Merlin SI RCD 40A 4P".

Cheers

 

[netblindpaul]

It was this then

Electrical Distribution

 

[clicon357]

It was this then

Electrical Distribution

Yes, that's the one.

 

[gerard]

Why a 1ph-3ph inverter when supply is 3ph? Or is it on 1ph supply?

It's a 1ph supply and they are the inverters used.

 

[gerard]

I called Schneider and they recommended a 40A(smallest they got), 300mA RCD with time delay. It's 23314. Watch this space!!

 

[clicon357]

I've called Schneider myself before and they were v.helpful. Did you mention that I am using a 30mA unit with inverters or did you explain your specific issue and they came up with the 300mA one? Just wondering what they had against using the 30mA Si unit?

 

[gerard]

The never mentioned a 30mA Si RCD. I mentioned that I had a 100mA RCD on the circuit and it kept tripping - hence the 300mA RCD

 

[clicon357]

The never mentioned a 30mA Si RCD. I mentioned that I had a 100mA RCD on the circuit and it kept tripping - hence the 300mA RCD

Odd, as I said previous we did at one time try 100mA RCDs but the site kicked off so we had to find a 30mA unit which worked. I personally didn't like the idea of higher than 30mA or time delay RCDs so the Si was a result. Might pay to bell them back and discuss the Si ones. I THINK I have the name of the Schneider guy I dealt with, will look tomorrow. Also can your inverter supplier not help, have they come across the issue?

 

[netblindpaul]

gerard, clicon357,

I am just wondering why the requirement for RCD's in your environments.
Can you please enlighten us a little, as I don't see the issues from where I am to be honest.
However, as I say from where I am, I don't have the insight to the environments that you do.

 

[clicon357]

gerard, clicon357,

I am just wondering why the requirement for RCD's in your environments.
Can you please enlighten us a little, as I don't see the issues from where I am to be honest.
However, as I say from where I am, I don't have the insight to the environments that you do.

Well I work on high rise buildings with "access equipment". So external, all weathers. Lots of 3 phase cabling supplying "cradles" or "building maintenance units". Cables from fixed outlets on the roof paid off from spring loaded drums on the machines themselves that travel round the roof edge on tracks. Then we have 3-phase cabling supplying the actual cradle (basket) that goes down the side of the building. Mechanical damage to junction boxes, limit switches / cable damage is a regular occurence with leads being run over and crushed. The people using the kit although trained to use it (and I mean no disrespect here) are only window cleaners. They want to get in press a button clean some glass and go home. Often shy of reporting damage etc. Often on a price, its a case of in/out and onto the next job. Some are even paid per "drop". Add in a couple of buckets of soapy water which sloshes about in the basket and drips over everything, wet hands changing cables etc.

 

[netblindpaul]

clicon,
If you are suffering this much damage then the equipment being used is not suitable for the application, you have a "selection & erection" issue.
However I do understand the use of RCD's, but, IMHO this is a sticking plaster on a severed limb approach.

 

[clicon357]

clicon,
If you are suffering this much damage then the equipment being used is not suitable for the application, you have a "selection & erection" issue.
However I do understand the use of RCD's, but, IMHO this is a sticking plaster on a severed limb approach.

You would have to understand the nature of my industry. Traditionally the cradles were simple wooden frames hoisted up the side of buildings with hemp ropes. Now we have fully powered cranes with industrial plcs some of which the users have to interface with. Whilst the kit has changed the people using it haven't. Lets be honest if they were that technically adept they wouldn't spend their days wiping dirt off glass which it what it comes down to. Its not that well paid and clients won't pay for what they see as a menial job. Its sometimes an abusive environment with time pressures. Also at the top of the building it's a case of out of sight out of mind for some clients. Bottom line is that I ventured a solution to a similar problem experienced by the OP, it worked and continues to work. Can't add much more than that really.....................

 

[netblindpaul]

Clicon,
I am not criticising you solution per se, even though I am! Sorry!
IMHO I believe that I could prove that it does not meet CDM, EAWR89, & PUWER98.
IMHO your solution relies on what is now additional protection, rather than "fundamental" protection of the circuits.
Not quite the right terminology, but I am using it that way to try to illustrate a point.

 

[gerard]

This is just my experience - and I'm sure they are all not the same. I work in a factory - if someone gets a static shock there is a big fuss, they have to go home, fill in accident reports, take time off and with today's 'compo' culture, god knows what else. Hence the reason to have everything to standard

 

[netblindpaul]

gerard,
A "static" shock will be nothing to do with the fixed wiring installation.
In a factory environment, there are really very very limited requirements in BS7671 for RCD's.

 

[gerard]

gerard,
A "static" shock will be nothing to do with the fixed wiring installation.
In a factory environment, there are really very very limited requirements in BS7671 for RCD's.

I understand that - I am just making a point and I don't want to take any chances. If it is possible to put an RCD on the circuit - I will