B type rcd's do you fit them ?

[rompling]

I haven't come across many type b rcd's are they widely used yet ?
Getting a new megger 1720 or 1730 the more expensive one (1730) States it tests them but the other does not
Is it worth the extra cash ?
I know the 1730 has Bluetooth and the earth electrode kit but I won't use them so it would only be getting the 1730 for the ability to test b type rcd's or just stick with the 1720
Thoughts ?

 

[Hawkmoon]

I recently had this exact same dilemma - I went with the 1720 in the end (like you, not interested in the bluetooth), I weighed up the price difference and decided to take the risk - may regret it though.

 

[ChrisElectrical88]

Seen millions of b type RCBOs. In schools and houses, why would you put a C type on a house circuit!

 

[Silly Sausage]

seen millions of b type rcbos. In schools and houses, why would you put a c type on a house circuit!

eh?!?!?

 

[GLENNSPARK]

I haven't come across many type b rcd's are they widely used yet ?
Getting a new megger 1720 or 1730 the more expensive one (1730) States it tests them but the other does not
Is it worth the extra cash ?
I know the 1730 has Bluetooth and the earth electrode kit but I won't use them so it would only be getting the 1730 for the ability to test b type rcd's or just stick with the 1720
Thoughts ?

why not?

down on the farm?

 

[rompling]

Sorry I'm confused
If that they are that widely used why does megger make a big selling point of the 1730 tests them ? If it's an industry standard as one poster implies ( and I'm not come across many ) than surely all newish MFT 's test them ?

 

[Rockingit]

Can we just clarify what we're talking about here?!

RCBO's or RCD's ? As only one of those makes any sense.

 

[rompling]

Sorry using the terminology off the isswww web site
"MFT1730 - The most sophisticated of the 17th Edition testers brings Type B RCD testing, 3-pole earth electrode testing to a downloading "

But imagine its RCBO 's - apologies if I'm being a dunce but the blurb above makes it sound like it's the only tester that tests type b -
A big outlay for most sparkys want to make sure I get a decent new MFT but not spend cash in features I might not use
Thanks for any replies

 

[HandySparks]

I think people are confusing Type B RCD sensitivity (ie DC superimposed and other odd waveforms) and type B overcurrent protection.

From Wikipedia:

Standard IEC 60755 (General requirements for residual current operated protective devices) defines three types of RCD depending on the characteristics of the fault current.
Type AC: RCD for which tripping is ensured for residual sinusoidal alternating currents

Type A: RCD for which tripping is ensured as for type AC
for residual pulsating direct currents
for residual pulsating direct currents superimposed by a smooth direct current of 6 mA, with or without phase-angle control, independent of the polarity

Type B: RCD for which tripping is ensured as for type A
for residual sinusoidal currents up to 1 kHz
for residual sinusoidal currents superposed by a pure direct current
for pulsating direct currents superposed by a pure direct current
for residual currents which may result from rectifying circuits three pulse star connection or six pulse bridge connection
two pulse bridge connection line-to-line with or without phase-angle monitoring, independently of the polarity


Edit: Typically required when protecting circuits with solar invertors (as I understand it).