IET logo
 
IET
Decrease font size
Increase font size
Topic Title: Dorman Smith Load Master
Topic Summary: What type?
Created On: 14 January 2013 06:40 PM
Status: Post and Reply
Linear : Threading : Single : Branch
Search Topic Search Topic
Topic Tools Topic Tools
View similar topics View similar topics
View topic in raw text format. Print this topic.
 14 January 2013 06:40 PM
User is offline View Users Profile Print this message



primo

Posts: 439
Joined: 10 January 2008

Came across a Dorman Smith Loadmaster DB today on a domestic. I had a good look at the info on a breaker but I'm sure it didn't state what type it was (i.e. 1/2/3/4 or B/C/D)

The breaking capacity was M1.5 which doesn't seems to correspond to any of the info I have found on line or from previous threads which seem to suggest that they are generally M3. Does this help to identify the type designation of 3871 that this is?

Any help much appreciated as want to make sure I get my facts straight!
 14 January 2013 06:51 PM
User is offline View Users Profile Print this message



John Peckham

Posts: 7520
Joined: 23 April 2005

That would appear to be a BS3871 MCB rated at 1.5kA. Any other information on the breaker? A lot of these were the dreaded Type 4 types.

-------------------------
John Peckham

http://www.astutetechnicalservices.co.uk/
 14 January 2013 07:35 PM
User is offline View Users Profile Print this message



primo

Posts: 439
Joined: 10 January 2008

Unfortunately not John, that's the trouble!

Definitely 3871 1.5kA but no other ino on it.
 14 January 2013 08:04 PM
User is offline View Users Profile Print this message



Phoenix151

Posts: 77
Joined: 14 February 2007

The original loadmaster was type 4 and breaking capacity of M3 (except 5A), toggle was 8-10mm wide (pic: http://www.dormansmithswitchge...ts/loadmaster_mcb.gif) and ratings of 5, 7.5, 15, 30, etc


See here for zs values: http://www.dormansmithswitchge...dmaster_datasheet.pdf

The loadmaster series 15 was type 3 and M4.5 breaking capacity and the toggle was 15-20mm wide (pic: http://electricsoutdoors.co.uk...ges/5076dc31f2cf0.jpg) and ratings of 6, 16, 32 etc

Zs values for type 3 are the same as type C but see here http://www.dormansmithswitchge...master-LXV_Zs_data.pdf for manufacturers data

Loadmaster was used in late 60's / 70's. series 15 came in later on in 80's. However breakers got mixed and matched, boards that are marked as series 15 often contain a mix of the two types, as series 15 is no longer available, but some ratings of original loadmaster are still made

Check your thermal withstand if using reduced CSA cpcs on the loadmaster breakers
 14 January 2013 09:33 PM
User is offline View Users Profile Print this message



primo

Posts: 439
Joined: 10 January 2008

Thanks for the info. Phoenix. I was thrown a little by the 1.5 rating on the 5a as that's the only one I checked and it didn't correspond with any of the info I'd found. I did see the data sheet and it is that series.

Cheers.
Statistics

See Also:



FuseTalk Standard Edition v3.2 - © 1999-2014 FuseTalk Inc. All rights reserved.